General fact: 6273 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 6273 is the number of ways to 9-color the vertices of a pentagon, up to rotations and reflections.
Trivia: 6273 is an unremarkable number.
Historical date: March 4th is the day in 1996 that a derailed train in Weyauwega, Wisconsin, US, causes the emergency evacuation of 2,300 people for 16 days.