general_fact: 5171 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 5171 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 5171 is an uninteresting number.
historical_date: February 26th is the day in 1909 that Kinemacolor, the first successful color motion picture process, is first shown to the general public at the Palace Theatre in London.