General fact: 21571 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 21571 is a boring number.
Trivia: 21571 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: January 21st is the day in 1968 that a B-52 bomber crashes near Thule Air Base, contaminating the area after its nuclear payload ruptures.