Fatto generale: 21089 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 21089 is an unremarkable number.
Trivia: 21089 is an uninteresting number.
Data storica: September 26th is the day in 1914 that the United States Federal Trade Commission (FTC) is established by the Federal Trade Commission Act.