Numbers 3:45-51

3:45 “Take the Levites instead of all the firstborn males among the Israelites, and the livestock of the Levites instead of their livestock. And the Levites will be mine. I am the Lord. 3:46 And for the redemption of the 273 firstborn males of the Israelites who exceed the number of the Levites, 3:47 collect five shekels for each one individually; you are to collect this amount in the currency of the sanctuary shekel (this shekel is twenty gerahs). 3:48 And give the money for the redemption of the excess number of them to Aaron and his sons.”

3:49 So Moses took the redemption money from those who were in excess of those redeemed by the Levites. 3:50 From the firstborn males of the Israelites he collected the money, 1,365 shekels, according to the sanctuary shekel. 3:51 Moses gave the redemption money to Aaron and his sons, according to the word of the Lord, as the Lord had commanded Moses.