40 years (and multiples of 40 years)

40 years times 15; 40 days and 40 nights
Gen 7:11-12
In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, on that day all the fountains of the great deep were broken up, and the windows of heaven were opened. And the rain was on the earth forty days and forty nights.

Married at 40 years
Gen 25:20
Isaac was forty years old when he took Rebekah as wife, the daughter of Bethuel the Syrian of Padan Aram, the sister of Laban the Syrian.

Gen 26:34-35
When Esau was forty years old, he took as wives Judith the daughter of Beeri the Hittite, and Basemath the daughter of Elon the Hittite. And they were a grief of mind to Isaac and Rebekah.

40 years of manna
Ex 16:35
And the children of Israel ate manna forty years, until they came to an inhabited land; they ate manna until they came to the border of the land of Canaan.

40 years in the wilderness
Num 32:13
So the Lord's anger was aroused against Israel, and He made them wander in the wilderness forty years, until all the generation that had done evil in the sight of the Lord was gone.
40 years reigning over Israel
1 Kings 2:11-12
The period that David reigned over Israel was forty years; seven years he reigned in Hebron, and in Jerusalem he reigned thirty-three years. Then Solomon sat on the throne of his father David; and his kingdom was firmly established.

2 Chron 9:30
Solomon reigned in Jerusalem over all Israel forty years.

Moses' 40 year events
And Moses was learned in all the wisdom of the Egyptians, and was mighty in words and deeds.

"Now when he was forty years old, it came into his heart to visit his brethren, the children of Israel. And seeing one of them suffer wrong, he defended and avenged him who was oppressed, and struck down the Egyptian. For he supposed that his brethren would have understood that God would deliver them by his hand, but they did not understand. And the next day he appeared to two of them as they were fighting, and tried to reconcile them, saying, 'Men, you are brethren; why do you wrong one another?' But he who did his neighbor wrong pushed him away, saying, 'Who made you a ruler and a judge over us? Do you want to kill me as you did the Egyptian yesterday?' Then, at this saying, Moses fled and became a dweller in the land of Midian, where he had two sons.

"And when forty years had passed, an Angel of the Lord appeared to him in a flame of fire in a bush, in the wilderness of Mount Sinai. When Moses saw it, he marveled at the sight; and as he drew near to observe, the voice of the Lord came to him, saying, 'I am the God of your fathers — the God of Abraham, the God of Isaac, and the God of Jacob.' And Moses trembled and dared not look. 'Then the Lord said to him, "Take your sandals off your feet, for the place where you stand is holy ground. I have surely seen the oppression of My people who are in Egypt; I have heard their groaning and have come down to deliver them. And now come, I will send you to Egypt."'

"This Moses whom they rejected, saying, 'Who made you a ruler and a judge?' is the one God sent to be a ruler and a deliverer by the hand of the Angel who appeared to him in the bush. He brought them out, after he had shown wonders and signs in the land of Egypt, and in the Red Sea, and in the wilderness forty years. (Acts 7:22-36)