Fatto matematico: 81370 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 81370 is an unremarkable number.
Data storica: October 13th is the day in 1917 that the "Miracle of the Sun" is witnessed by an estimated 70,000 people in the Cova da Iria in Fátima, Portugal.