Fait général: 8340 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 8340 is a value of n so that (n-1)^{2} + n^{2} + (n+1)^{2} is a palindrome.
Culture générale: 8340 is an unremarkable number.
Date historique: October 31st is the day in 1999 that EgyptAir Flight 990 traveling from New York City to Cairo crashes off the coast of Nantucket, Massachusetts, killing all 217 on-board.