general_fact: 13864 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 13864 is an unremarkable number.
trivia: 13864 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: December 15th is the day in 1467 that Stephen III of Moldavia defeats Matthias Corvinus of Hungary, with the latter being injured thrice, at the Battle of Baia.