Fait mathématique: 21744 is an uninteresting number.
Culture générale: 21744 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: July 13th is the day in 1793 that Journalist and French revolutionary Jean-Paul Marat is assassinated in his bathtub by Charlotte Corday, a member of the opposing political faction.