Fatto generale: 21585 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21585 is a boring number.
Trivia: 21585 is a boring number.
Data storica: February 4th is the day in 1977 that a Chicago Transit Authority elevated train rear-ends another and derails, killing 11 and injuring 180, the worst accident in the agency's history.