Numbers 1:44-47
1:44 These were the men whom Moses and Aaron numbered along with the twelve leaders of Israel, each of whom was from his own family.
1:45 All the Israelites who were twenty years old or older, who could serve in Israel’s army, were numbered according to their families.
1:46 And all those numbered totaled 603,550.
The Exemption of the Levites
1:47 But the Levites, according to the tribe of their fathers, were not numbered among them.