Fatto generale: 63840 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 63840 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 63840 is an unremarkable number.
Data storica: October 14th is the day in 1939 that the German submarine U-47 sinks the British battleship HMS Royal Oak within her harbour at Scapa Flow, Scotland.