Fatto generale: 8131 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 8131 is an uninteresting number.
Trivia: 8131 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: April 5th is the day in 1609 that Daimyo (Lord) of the Satsuma Domain in southern Kyūshū, Japan, completes his successful invasion of the Ryūkyū Kingdom in Okinawa.