General fact: 16647 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 16647 is a boring number.
Trivia: 16647 is an unremarkable number.
Historical date: July 29th is the day in 1907 that Sir Robert Baden Powell sets up the Brownsea Island Scout camp in Poole Harbour on the south coast of England.