Fatto generale: 90821 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 90821 is an uninteresting number.
Trivia: 90821 is a boring number.
Data storica: August 28th is the day in 475 that the Roman general Orestes forces western Roman Emperor Julius Nepos to flee his capital city, Ravenna.