general_fact: 91841 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 91841 is an unremarkable number.
trivia: 91841 is an unremarkable number.
historical_date: June 14th is the day in 1966 that the Vatican announces the abolition of the Index Librorum Prohibitorum (index of prohibited books), which was originally instituted in 1557.