Charles Ellicott Commentary 1 Chronicles 7:9

"And they were reckoned by genealogy, after their generations, heads of their fathers` houses, mighty men of valor, twenty thousand and two hundred." — 1 Chronicles 7:9 (ASV)

And the number ... —Render, “And their census (hithyahsâm) according to their genealogies, heads of their clans, valiant warriors, was 20,200.” This means that the total number of the warriors of Becher, chiefs with clans, was 20,200. “Their census:” that is, the census of the chiefs who are regarded as one with their clans. Others assume that the names in these registers are merely those of supposed founders of the clans; eponyms like Hellen, Ion, Dorus, etc., or Italus, Latinus, Romulus, and Remus.