Fatto generale: 20535 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 20535 is an unremarkable number.
Trivia: 20535 is an unremarkable number.
Data storica: March 21st is the day in 1925 that Syngman Rhee is removed from office after being impeached as the President of the Provisional Government of the Republic of Korea.