Fatto generale: 20813 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 20813 is an unremarkable number.
Trivia: 20813 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: December 24th is the day in 1818 that the first performance of "Silent Night" takes place in the church of St. Nikolaus in Oberndorf, Austria.