According to Bible apologists:
https://www.apologeticspress.org/apcontent.aspx?category=6&article=796
Critics of the 215-year view, however, have suggested that the second 215-year period (i.e., the time spent in Egypt) would not allow for the population explosion that obviously occurred while the Hebrews were captives. Less than 100 went down into Egypt, and yet by the time they left, they numbered more than 2 million (based on the figures in Numbers 1:46; cf. Archer, 1982, pp. 378-379). However, C.G. Ozanne, in his volume, The First 7,000 Years, has shed some light on this criticism.
Of course, the standard objection to this interpretation is the census totals of male Levites in Numbers 3. In this chapter the total number of Kohath’s male descendants “from a month old and upward” is given as 8600 (v. 28), these being divided between his four sons, Amram, Izhar, Hebron, and Uzziel. Assuming that the total number is to be divided evenly between the four sons, Amram must have had some 2150 male descendants within a few months of the Exodus. At first sight this figure may seem well-nigh impossible. When, however, it is broken down, it begins to assume more reasonable proportions. Thus, supposing that Amram was born fifty-five years after the descent into Egypt and that forty years constitute a generation, it is only necessary to allocate seven males to a family to arrive at a figure considerably in excess of the desired 2150. On this reckoning Moses would have had 7 brothers (for he himself may be ignored for the purposes of this calculation), 49 nephews, 343 great-nephews and 2401 great-great-nephews within the allotted span. A total of 2800 is thus obtained, of which the vast majority would still have been alive to see the exodus from Egypt. Bearing in mind the greatly extended period of childbearing (Jochebed was about 70 at the birth of Moses), the practice of polygamy (which enabled Jacob to have eleven sons in seven years), and above all the astonishing fertility of the Israelite women on which the Bible lays special emphasis (cf. Gen. 46.3; Exod. 1.7,12,19; Deut. 26.5), the rate of increase here suggested should not necessarily be thought incredible (1970, pp. 22-23).