Two million is actually a very conservative estimate, considering the 600k or so were adult men on foot. If we include women, children and men who could not walk long distances, the number may have been closer to three million. And this does not even count the "mixed multitude" and vast numbers of cattle:
Exodus 12:37-38
About six hundred thousand men on foot, not counting the children. A
crowd of mixed ancestry also went up with them, with livestock in
great abundance, both flocks and herds.
For critical scholars the problem is not so much Deuteronomy's "fewest of all peoples" but the large number given in Exodus. These Israelites and their mixed-race followers - a number larger than the world's greatest city at the time - left no archaeological remains during their 40 years in the wilderness. No wonder many believers, as well as skeptics, understand this number to be exaggerated.
There is also an issue in the text itself, which states - much more credibly - that the whole number of first-born males was about 22,000.
Numbers 3
42 So Moses enrolled all the firstborn of the Israelites, as the Lord
had commanded him. 43 All the firstborn males, registered by name, of
a month or more, numbered twenty-two thousand two hundred and
seventy-three.
It is a mathematical impossibility that 22,000 first-born males would form the core or a fighting force of 600,000 thousand men. If my math is right this would boil down to about 27 brothers for every first-born male (not including their sisters).
Conclusion: We may never know whether Deuteronomy's "fewest of all" or the Book of Numbers' 600,000 men on foot is more accurate. The important thing is not the numbers themselves, but the fact that they left the realm of Pharaoh's domain, and God was with them.
