The Rabbis accounted for these “ut lætior esset Israelitarum reditus,” in order that the return of the Israelites might be more joyful; but they were hired for lamentation as well as joy; and here, possibly, to supply the defect of Levites. In Nehemiah (Nehemiah 7:67) there are 245: see for the probable reason of the mistranscription the 245 of the next verse in that chapter.
Related Commentaries of Ezra 2:65
Ezra 2:65
65 Beside their servants and their maids, of whom there were seven thousand three hundred thirty and seven: and there were among them two hundred singing men and singing women.