Fait mathématique: 5611 is the smallest number for which it and the 3 numbers before and after it all have f(n) divisible by 10.
Culture générale: 5611 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: May 12th is the day in 2006 that Mass unrest by the Primeiro Comando da Capital begins in São Paulo (Brazil), leaving at least 150 dead.