Exodus 12:37 refers to 600,000 adult Hebrew men leaving Egypt with Moses, plus an unspecified but apparently large "mixed multitude" of non-Hebrews; Numbers 1:46 gives a more precise total of 603,550. If taken literally the total number involved, the 600,000 "fighting men" plus wives, children, the elderly, and the "mixed multitude," would have been two million or more,equivalent to something between half and almost the entire Egyptian population of around 3-6 million.
The loss of such a huge proportion of the population would have caused havoc to the Egyptian economy, yet no such effect has been discovered. Archaeological research has found no evidence that the Sinai desert ever hosted, or could have hosted, millions of people, nor of a massive population increase in Canaan, estimated to have had a population of between 50,000 and 100,000, at the end of the march. The logistics involved also present problems: Eric Cline, points out that 2.5 million people marching ten abreast would form a line 150 miles long, without accounting for livestock.