Fait général: 1684 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 1684 is the number of multigraphs with 6 vertices and 9 edges.
Culture générale: 1684 is a boring number.
Date historique: August 10th is the day in 1932 that a 5.1 kilograms (11 lb) chondrite-type meteorite breaks into at least seven pieces and lands near the town of Archie in Cass County, Missouri.