Fait mathématique: 81497 is an unremarkable number.
Culture générale: 81497 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: February 17th is the day in 1500 that Duke Friedrich and Duke Johann attempt to subdue the peasantry of Dithmarschen, Denmark, in the Battle of Hemmingstedt.