Numbers 3:39-43

All the numbered men of the Levites, whom Moses and Aaron counted at the command of the Lord by their families, every male from a month old and upward, were twenty-two thousand. Firstborn Redeemed

Then the Lord said to Moses, “Count every firstborn male of the sons of Israel from a month old and upward, and make a list of their names.

And you shall take the Levites for Me—I am the Lord—instead of all the firstborn among the sons of Israel; and the cattle of the Levites in place of all the firstborn among the cattle of the sons of Israel.”

So Moses counted all the firstborn among the sons of Israel, just as the Lord had commanded him;

and all the firstborn males, by the number of names from a month old and upward for their numbered men, were 22,273.