general_fact: 4644 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 4644 is a value of n for which 7n and 9n together use each digit exactly once.
trivia: 4644 is an unremarkable number.
historical_date: September 17th is the day in 1631 that Sweden wins a major victory at the Battle of Breitenfeld against the Holy Roman Empire during the Thirty Years War.