general_fact: 16816 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 16816 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 16816 is a boring number.
historical_date: January 14th is the day in 1343 that Arnošt of Pardubice becomes the last bishop of Prague and, subsequently, the first Archbishop of Prague.