math_fact: 23729 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 23729 is a boring number.
historical_date: December 18th is the day in 1898 that Gaston de Chasseloup-Laubat sets the first officially recognized land speed record of 39.245 mph (63.159 km/h) in a Jeantaud electric car.