Fatto matematico: 6816 is the index of a triangular number containing only 3 different digits.
Trivia: 6816 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: August 29th is the day in 1991 that Libero Grassi, an Italian businessman from Palermo is killed by the Mafia after taking a solitary stand against their extortion demands.