Fatto generale: 21445 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21445 is an uninteresting number.
Trivia: 21445 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: September 17th is the day in 2001 that the New York Stock Exchange reopens for trading after the September 11 Attacks, the longest closure since the Great Depression.