general_fact: 5371 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 5371 is a value of n for which n and 8n together use each digit 1-9 exactly once.
trivia: 5371 is a boring number.
historical_date: September 14th is the day in 1958 that the first two German post-war rockets, designed by the German engineer Ernst Mohr, reach the upper atmosphere.