Fatto generale: 8661 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 8661 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 8661 is an unremarkable number.
Data storica: September 17th is the day in 1631 that Sweden wins a major victory at the Battle of Breitenfeld against the Holy Roman Empire during the Thirty Years War.