Asked in Tanakh and Talmud
How many were the Israelites when they were leaving Egypt?
The mature men were about 600,000 (Exodus 12:37), plus the 22,000 Levites (Numbers 3:39). To this must be added the converts (Exodus 12:38), and the women and children. Based on the ratio of firstborn to younger children (Numbers ch.3), it can be seen that the children were numerous. Estimates for the total number are usually given at two million or more.See also:
The Bible gives the following information on the number one to two years after they left Egypt:
Numbers 1:45-46 (KJV) 45 So all of the children of Israel that were counted, by the house of their fathers, from twenty years old and upward, all that were able to go forth to war in Israel, were six hundred thousand and three thousand and five hundred and fifty.
It has been extrapolated from these figures that the likely total was somewhere around two million individuals.