general_fact: 13491 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 13491 is an unremarkable number.
trivia: 13491 is a boring 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.