Numbers 1:45-46 So all those listed of the people of Israel, by their fathers' houses, from twenty years old and upward, every man able to go to war in Israel — all those listed were 603,550.
It can certainly be questioned if the Exodus ever happened at all, but assuming it did, are the population numbers described in the Book of Numbers reasonable? What kind of impact would a population of nearly 2 million Israelites have on the region? Are there any translation complications that might explain the seemingly high numbers? When were these bible stories written and could the time between the event and its transcription account for any inflated or exaggerated values?
The population figures in Numbers are accurate - The literal interpretation of the population size must be accurate because the Bible is infallible. It is also not unreasonable to believe that a population growth rate necessary to achieve this figure is within the realm of possibility. Miracles can easily account for the group's survival in the wilderness. (The Number of the Exodus) (Got Questions?: Are the numbers in the Bible accurate?) (Defending Inerrancy: How accurate is the census of the Tribes of Israel?)
The population figures in Numbers are too large - The literal interpretation of the population size is inaccurate. There are many other verses in the Bible that seem to contradict or at least bring into question the idea of a large Israelite population. There are also several possible translation issues that may account for a smaller population which would be much more reasonable in the historical setting. (James Bishop: A Small Israelite Exodus Population) (Lee Harmon: How many Israelites wandered in the desert?)
The population figures in Numbers are symbolic or the result of translation errors - "The skeptic is satisfied with such reasoned explanations, as they do not assume unnecessary elements such as divine entities. However, for the biblical inerrantist, who believes the narrative came directly from God, such a suggestion is unthinkable. And so we come full circle. As a biblical inerrantist one must conclude ... that the stories of the Bible do not strain credulity as long as one does not theorize editorial blunders to, or literary conventions in, the text which turn the omniscient deity into a buffoon unable to preserve his sacred text and as long as one does not scratch the surface of historical reality too deeply to reveal the flaws such a reality exposes in the narratives." (The Skeptical Review: Playing the Numbers Game, A Critique of Attempts to Rationalize the Population Numbers of Exodus)
The evidence does not support the population figures in Numbers - "The 600,000, plus wives, children, the elderly, and the "mixed multitude" of non-Israelites would have numbered some 2 million people. Marching ten abreast, and without accounting for livestock, they would have formed a line 150 miles long. The entire Egyptian population in 1250 BCE is estimated to have been around 3 to 3.5 million, and no evidence has been found that Egypt ever suffered the demographic and economic catastrophe such a loss of population would represent, nor that the Sinai desert ever hosted (or could have hosted) these millions of people and their herds." (Wikipedia: The Exodus - Numbers and Logistics)
Numbers 1:45, Numbers 1:46