Albert Barnes Commentary Numbers 26:62

"And they that were numbered of them were twenty and three thousand, every male from a month old and upward: for they were not numbered among the children of Israel, because there was no inheritance given them among the children of Israel." — Numbers 26:62 (ASV)

The total number of male Levites, 23,000, shows an increase of 1,000 on the number at Sinai (Numbers 3:39). It is doubtless to be taken as a round number; and, as before, includes the male children from a month old and upward, as well as the male adults.