Fatto generale: 13573 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 13573 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 13573 is an uninteresting number.
Data storica: February 27th is the day in 1617 that Sweden and Russia sign the Treaty of Stolbovo, ending the Ingrian War and shutting Russia out of the Baltic Sea.