Mathematical fact: 5401 is a member of the Fibonacci-type sequence starting with 3 and 7.
Trivia: 5401 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: 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.