general_fact: 49939 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 49939 is an uninteresting number.
trivia: 49939 is an unremarkable number.
historical_date: September 22nd is the day in 1857 that the Russian warship Lefort capsizes and sinks during a storm in the Gulf of Finland, killing all 826 aboard.