Genesis 47:27-28

"And Israel dwelt in the land of Egypt, in the land of Goshen; and they got them possessions therein, and were fruitful, and multiplied exceedingly. And Jacob lived in the land of Egypt seventeen years: so the days of Jacob, the years of his life, were a hundred and forty and seven years."

If only a hundred went down into Egypt with Jacob, a five percent annual growth rate would have put them over 200 by the time Jacob died. By the time of the Exodus, their number had reached over 2,000,000, with over 600,000 fighting men above the age of twenty (Numbers 1:46)!