After Joseph’s family settled in the land of Goshen, they increased greatly in number:
But the people of Israel were fruitful and increased greatly; they multiplied and grew exceedingly strong, so that the land was filled with them (Exodus 1:7).
And the people of Israel journeyed from Rameses to Succoth, about six hundred thousand men on foot, besides women and children (Exodus 12:37).
I found a useful article that helps to answer your question. It gives an explanation of how the Hebrew words for different numbers could have been misinterpreted. It also agrees that the post-exodus Israelite army numbered well over 600 thousand men. This would imply a total Israeli population of about 2.4 million. This information is in addition to, and in support of, Dottard’s answer:
The Hebrew term ‘eleph is typically translated “thousand” (Exodus 18:21), such as in the first chapter of Numbers. The counts given in this chapter are composed of words, not numerals. Numbers 1:21, for instance, records the men of Reuben’s tribe as sis’sāh vav arbā’im ‘eleph vav hamēs mē’ot.” The traditional, literal translation would be “six and forty thousand and five hundred,” usually rendered as “46,500.”
However, two words in this phrase are subject to variations: ‘eleph and vav. The term ‘eleph is used elsewhere in Scripture as a reference to groups, not a literal number, including descriptions of Israel during and after the exodus. It is applies to tribes (Numbers 10:4), clans (Joshua 22:14; Judges 6:15; Micah 5:1), families (Joshua 22:21), and divisions (Numbers 1:16).
Further, the connecting symbol vav can mean “and,” but it can also mean “or,” depending on context. Exodus 21:15 and Exodus 21:17, for instance, use vav to imply that certain actions are a sin when done against one’s father “or” mother, not that they are sins when done against them both.
The total for the final tally given in Numbers 1:46, likewise, might have been intended as “598 ‘eleph, or 5,500,” then accidentally misread as “598 ‘eleph and 5 ‘eleph and 500,” which was condensed to “603,500” as misinterpretation of the prior passage took hold.
Exodus 12:37, Numbers 1:46, and Numbers 2:32 all describe Israel’s population of men, not including women and children. Numbers 1:21–43 gives an account from each tribe, using Hebrew words, not symbols, to represent quantities. Adding these up, one arrives at the figure given in verse 46. This phrasing is traditionally interpreted to mean just over 600 thousand adult men, implying a total population about four times that size, or 2.4 million. Source: https://www.gotquestions.org/Israelites-exodus.html
There are counter-arguments to a large contingent of Israeli’s leaving Egypt (as explained in the article above) that are worth reading, but the article comes to this conclusion:
Scripture does not place any theological significance on the exact number of people who participated in the exodus. The intent of the Old Testament is to record God’s intervention on Israel’s behalf and their response to those signs. The fact that the Bible gives little space, other than a few verses, referring to the numbers of people implies that those numbers are not crucial in and of themselves. That there is confusion about what those numbers are has more to do with our lack of understanding than some subtle point being made by God. Both the “large Israel” and “small Israel” interpretations—solutions one and two, above—have supporters and detractors. Both have strengths and weaknesses. They cannot both be true, but either one would be compatible with a view of Scripture as inerrant and inspired.
