40Then the LORD said to Moses, “Number every firstborn male of the Israelites a month old or more, and list their names.
41You are to take the Levites for Me — I am the LORD — in place of all the firstborn of Israel, and the livestock of the Levites in place of all the firstborn of the livestock of the Israelites.”
42So Moses numbered all the firstborn of the Israelites, as the LORD had commanded him.
43The total number of the firstborn males a month old or more, listed by name, was 22, 273.
— Numbers 3:40-43