Fait mathématique: 9321 is a value of n for which n and 8n together use each digit 1-9 exactly once.
Culture générale: 9321 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: July 8th is the day in 1932 that the Dow Jones Industrial Average reaches its lowest level of the Great Depression, bottoming out at 41.22.