Brown Driver Briggs

 Hattush = "assembled"
1. a descendant of David, apparently one of the sons of Shechaniah,
in the 4th or 5th generation from Zerubbabel
  1) a man who returned with Ezra; maybe same as 1 above
  2) a man who returned with Zerubbabel; maybe same as 1 above
2. son of Hashabniah who helped repair the walls of Jerusalem with
Nehemiah