Fait mathématique: 13543 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 13543 is an unremarkable number.
Date historique: January 28th is the day in 1980 that USCGC Blackthorn collides with the tanker Capricorn while leaving Tampa Florida and capsizes killing 23 Coast Guard crewmembers.