Fait général: 6481 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 6481 is (3^{12} + 1) / (3^{4} + 1).
Culture générale: 6481 is a boring number.
Date historique: September 28th is the day in 1971 that the Parliament of the United Kingdom passes the Misuse of Drugs Act 1971 banning the medicinal use of cannabis.