Fatto generale: 6204 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 6204 is an uninteresting number.
Trivia: 6204 is a boring number.
Data storica: December 25th is the day in 1991 that Mikhail Gorbachev resigns as president of the Soviet Union (the union itself is dissolved the next day).