Fatto generale: 21742 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21742 is an uninteresting number.
Trivia: 21742 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: July 11th is the day in 1972 that the first game of the World Chess Championship 1972 between challenger Bobby Fischer and defending champion Boris Spassky starts.