general_fact: 13787 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 13787 is an unremarkable number.
trivia: 13787 is an unremarkable number.
historical_date: September 29th is the day in 2004 that the Burt Rutan Ansari X Prize entry SpaceShipOne performs a successful spaceflight, the first of two required to win the prize.