Fait mathématique: 2911 is a value of n for which s(n-1) = s(n+1).
Culture générale: 2911 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: December 20th is the day in 1988 that the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances is signed in Vienna.