Mathematical fact: 7312 is a value of n for which n and 8n together use each digit 1-9 exactly once.
Trivia: 7312 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: January 7th is the day in 1991 that Roger Lafontant, former leader of the Tonton Macoutes in Haiti under François Duvalier, attempts a coup d'état, which ends in his arrest.