General fact: 4399 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 4399 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 4399 is an uninteresting number.
Historical date: January 16th is the day in 1707 that the Scottish Parliament ratifies the Act of Union, paving the way for the creation of Great Britain.