Fatto generale: 21779 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21779 is a boring number.
Trivia: 21779 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: August 17th is the day in 2008 that American swimmer Michael Phelps becomes the first person to win eight gold medals in one Olympic Games.