general_fact: 15909 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 15909 is an uninteresting number.
trivia: 15909 is a boring number.
historical_date: July 22nd is the day in 1933 that Wiley Post becomes the first person to fly solo around the world traveling 15,596 miles (25,099 km) in 7 days, 18 hours and 45 minutes.