Some have asserted that the huge numbers of people listed in various places in Exodus and Numbers are impossible or unlikely for a number of real-world reasons. Those include lack of mention of such big numbers in Egyptian and other secular accounts, archaeological estimates of populations at the time, food supply and other logistics for such huge numbers during the Exodus, number of years Israel was in Egypt, smaller numbers mentioned in the Bible hundreds of years later, trepidation of Israel to invade the Land despite having huge army, etc.
Rather than exegesis — a critical examination of a text from the text — this is eisegesis — a critical examination of a text from considerations outside the text.
What follows is a close study of the numbers listed in Numbers 1 (cf. Ex. 12:37 and 38:26), the pattern for which is used in following chapters and elsewhere in the Hebrew Bible. The plain reading of the text is that the Hebrew word אלף ’elef (Strong’s lexicon No. 505) means “thousand,” rather than “clan,” “chief,” or “group.”