general_fact: 91039 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 91039 is a boring number.
trivia: 91039 is an unremarkable number.
historical_date: April 3rd is the day in 1888 that the first of 11 unsolved brutal murders of women committed in or near the impoverished Whitechapel district in the East End of London, occurs.