Fatto generale: 21039 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21039 is an uninteresting number.
Trivia: 21039 is a boring number.
Data storica: August 7th is the day in 1998 that the United States embassy bombings in Dar es Salaam, Tanzania and Nairobi, Kenya kill approximately 212 people.