Fatto generale: 20504 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 20504 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 20504 is an uninteresting number.
Data storica: February 19th is the day in 1600 that the Peruvian stratovolcano Huaynaputina explodes in the most violent eruption in the recorded history of South America.