General fact: 7871 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 7871 is a boring number.
Trivia: 7871 is an unremarkable number.
Historical date: July 19th is the day in 1961 that Tunisia imposes a blockade on the French naval base at Bizerte; the French would capture the entire town four days later.