Numbers 3:44

41 And give to me the Levites (I am the Lord) in place of the first sons of the children of Israel; and the cattle of the Levites in place of the first births among the cattle of the children of Israel.

42 So Moses had all the first sons among the children of Israel numbered, as the Lord said to him.

43 Every first son from a month old and over was numbered by name, and the number came to twenty-two thousand, two hundred and seventy-three.

45 Take the Levites in place of all the first sons of the children of Israel, and the cattle of the Levites in place of their cattle; the Levites are to be mine; I am the Lord.

46 And the price you have to give for the two hundred and seventy-three first sons of the children of Israel which are in addition to the number of the Levites,

47 Will be five shekels for every one, by the scale of the holy place (the shekel is twenty gerahs);