Fatto generale: 21348 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21348 is an uninteresting number.
Trivia: 21348 is a boring number.
Data storica: June 12th is the day in 1979 that Bryan Allen wins the second Kremer prize for a man powered flight across the English Channel in the Gossamer Albatross.