Hecho general: 22539 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 22539 is a boring number.
Trivia: 22539 is an uninteresting number.
Fecha histórica: September 15th is the day in 1962 that the Soviet ship Poltava heads toward Cuba, one of the events that sets into motion the Cuban Missile Crisis.