Numbers 1:44-47

44These are the ones who were numbered, whom Moses and Aaron numbered, with the leaders of Israel, twelve men, each of whom was of his father’s household. 45So all the numbered men of the sons of Israel by their fathers’ households, from twenty years old and upward, whoever was able to go out to war in Israel, 46even all the numbered men were 1603,550.

472The Levites, however, were not numbered among them by their fathers’ tribe.