general_fact: 15859 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 15859 is an uninteresting number.
trivia: 15859 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: June 2nd is the day in 1910 that Charles Rolls, co-founder of Rolls-Royce Limited, becomes the first man to make a non-stop double crossing of the English Channel by plane.