Comparing the numbers here with those in Judges 20:16
See Judges 3:15, and note. In the Septuagint and Vulgate the 700 chosen men of Gibeah are represented as the seven hundred left-handed slingers.
SDA Bible Commentary (limited)
Volume 1-7
17. Four hundred thousand. The Israelite population was declining. In the first year after the Exodus from Egypt the fighting men are said to have numbered 603,550 including 35,400 from Benjamin (Num. 1:46, 37). In the 40th year after the Exodus they are said to have numbered 601,730, including 45,600 Benjamites (Num. 26:51, 41).