Fait général: 5100 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 5100 is divisible by its reverse.
Culture générale: 5100 is a boring number.
Date historique: December 17th is the day in 1967 that Prime Minister of Australia Harold Holt disappears while swimming near Portsea, Victoria and is presumed drowned.