Isaac was born the year 2067 BC. Isaac Birth year, and the feast of Ingathering are identified with the coming of Christ. A tropical year is 365.24218967 days. There are 1,489,464 days from the Feast of Ingathering in 2067 BC to the feast of Ingathering 2012 AD. The factors of 1,489,464 are: 24 (a day identified with length of Final Tribulation and the total that fell under plague during Israel wilderness journey), 3 (purpose) 137 (Death of Levi and Ishmael), 151 during the Flood the waters abate which are blessings for Noah in the ark and the Earth on the 151st Day).

Abraham was 100 years old when son Isaac was born unto him

Abraham was born in 2167 BC. A hundred years later would be the year 2067 BC.

Hebrews 11:17 By faith Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son,

Genesis 21:5 And Abraham was an hundred years old, when his son Isaac was born unto him.

The birth of Isaac clearly typified the coming of the Lord Jesus Christ. As Isaac is connected with the command of God given to Abraham to offer him up as a sacrifice on a mountain in the land of Moriah (Gen. 22). In the New Testament reference is made to his having been “offered up” by his father (Heb. 11:17; James 2:21), and to his blessing his sons (Heb. 11:20). As the child of promise, he is contrasted with Ishmael (Rom. 9:7, 10; Gal. 4:28; Heb. 11:18).

Hebrews 11:17 By faith Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son,

James 2:21 Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?

The feast of ingathering or end of a harvest year is identified with the coming of Christ

Matthew 20:8 So when even was come, the lord of the vineyard saith unto his steward, Call the labourers, and give them their hire, beginning from the last unto the first.

Matthew 13:39 The enemy that sowed them is the devil; the harvest is the end of the world; and the reapers are the angels

Exodus 23:16 And the feast of harvest, the firstfruits of thy labours, which thou hast sown in the field: and the feast of ingathering, which is in the end of the year, when thou hast gathered in thy labours out of the field.

Our Gregorian calendar aims to keep the vernal equinox on or close to March 21; hence, it follows the vernal equinox year. The average length of the Gregorian year is 365.2425 days. There is only a difference of 0.000302 (0.2425-0.242198) between the Tropical year (vernal equinox year) and a Gregorian Year. At this fractional difference, it would take 3,311 years just to generate one day of difference.

Tishri 15 in 2067 BC begins on Sept. 26- After 6 PM counts as new day, though under our reckoning of time it would still be the same day if recognized as 24 hours from 12:01 AM

Note:
 

Start of Jewish day: While it appears that, initially, the Hebrew day was reckoned from sunrise to sunset (Lev. 7:15-17), later when the new moon was used to determine months, the day was determined from sunset to sunset (Lev. 23:32; Neh. 13:19). During the time of Christ, the day started at sunset. That is why the Jews were anxious that he and the two thieves crucified with him died before sundown because the morrow was a "high day" (John 19:31).

Used freeware Intercal by Denis A Elliot

September 26-27, 2067 BC (Feast of Ingathering -Gregorian)

Used freeware Intercal by Denis A Elliot

October 1, 2012 AD (Feast of Ingathering -Gregorian)

There are 1,489,464 days between Tishri 15, (Feast of Ingathering - Sept. 26) 2067 BC and Tishri 15, (Feast of Ingathering - Oct. 1) 2012. The number 1,489,464 has factors of : 24 (a day identified with length of Final Tribulation and the total that fell under plague during Israel wilderness journey), 3 (purpose) 137 (Death of Levi and Ishmael), 151 during the Flood the waters abate which are blessings for Noah in the ark and the Earth on the 151st Day).

24 X 3 X 137 X 151 = 1,489,464
 

4,078 (years September 26, 2067 BC to September 26, 2012 AD) X 365.24218967 = 1,489,458 (rounded to the nearest day)

The total days from September 26, 2012 AD to October 1, 2012 = 6 days

1,489,458 days + 6 days = 1,489,464 days.

The number 24 is identified with the length of final tribulation and the total number that died in the plague:

Numbers 25:9 And those that died in the plague were twenty and four thousand.

Final Tribulation is identified with the length of a 24 year period( as an hour /as a day/as a year)

Revelation 9:15 And the four angels were loosed, which were prepared for an hour, and a day, and a month, and a year, for to slay the third part of men.

The number 3 is identified - with purpose or established by God:

Deuteronomy 19:15 One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sinneth: at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established.

The number 137 is life on earth of the True Believers typified by Levi the priest and the unbelievers typified by Ishmael the Son of bondwoman:

Genesis 21:10 Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac.

True believers are typified as priest:

1Peter 2:9 But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light:

Unbelievers are typified as children of bondwoman:

Galatians 4:29 But as then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now.
Galatians 4:30 Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman.
Galatians 4:31 So then, brethren, we are not children of the bondwoman, but of the free.

Levi's life on earth 137 years:

Exodus 6:16 And these are the names of the sons of Levi according to their generations; Gershon, and Kohath, and Merari: and the years of the life of Levi were an hundred thirty and seven years.

Ishmael's life on earth 137 years:

Genesis 25:17 And these are the years of the life of Ishmael, an hundred and thirty and seven years: and he gave up the ghost and died; and was gathered unto his people.

The number 151 waters abated at the end of 150 days are the beginning of the 151st day blessing for Naoh and flooded earth

Genesis 8:1 ¦ And God remembered Noah, and every living thing, and all the cattle that was with him in the ark: and God made a wind to pass over the earth, and the waters asswaged;
Genesis 8:2 The fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained;
Genesis 8:3 And the waters returned from off the earth continually: and after the end of the hundred and fifty days the waters were abated.

Proverbs 30:4 Who hath ascended up into heaven, or descended? who hath gathered the wind in his fists? who hath bound the waters in a garment? who hath established all the ends of the earth? what is his name, and what is his son's name, if thou canst tell?

Note
 

When the (Lord, God) bestows blessing upon the true believers it is in terms of God remembering his promise:

Genesis 19:29 And it came to pass, when God destroyed the cities of the plain, that God remembered Abraham, and sent Lot out of the midst of the overthrow, when he overthrew the cities in the which Lot dwelt.
 

Genesis 30:22 And God remembered Rachel, and God hearkened to her, and opened her womb.
 

Exodus 2:24 And God heard their groaning, and God remembered his covenant with Abraham, with Isaac, and with Jacob.

Judges 16:28 And Samson called unto the LORD, and said, O Lord GOD, remember me, I pray thee, and strengthen me, I pray thee, only this once, O God, that I may be at once avenged of the Philistines for my two eyes.
 

The stoppage of rain was identified with 151 years from the Judgment of Israel (Northern Kingdom) in the 14th year of King Ahab; when Elijah said to King Ahab," there shall not be dew nor rain these years" in 860 BC to the year 709 BC. Israel (Northern Kingdom) typified as Sodom was destroyed by Assyria in 709 BC. There are 2720 years (709 BC + 2011 years = 2012 AD) between 709 BC and the year 2012 AD. The factors of 2720 are :40 (trail or testing) X 17 (Heaven or Judgment) X 4 (Complete End/ 4 months Final Harvest).

1Kings 17:1 ¶ And Elijah the Tishbite, who was of the inhabitants of Gilead, said unto Ahab, As the LORD God of Israel liveth, before whom I stand, there shall not be dew nor rain these years, but according to my word.

Note

The rain was withheld for three years 860 BC to 857 BC. Israel (Northern Kingdom) was destroyed 148 years later from 857 BC to 709 BC. 148 is identified with the division of summer to the Feast of Ingathering and the days owed to early and latter rain -see 5 moths .Revelation 9-5 explained