General fact: 13856 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 13856 is an uninteresting number.
Trivia: 13856 is an unremarkable number.
Historical date: December 7th is the day in 1724 that Tumult of Thorn – religious unrest is followed by the execution of nine Protestant citizens and the mayor of Thorn (Toruń) by Polish authorities.