general_fact: 7880 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 7880 is the maximum value of n so that there exist 4 denominations of stamps so that every postage from 1 to n can be paid for with at most 26 stamps.
trivia: 7880 is an unremarkable number.
historical_date: July 28th is the day in 1935 that First flight of the Boeing B-17 Flying Fortress.