Fatto generale: 6337 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 6337 is an unremarkable number.
Trivia: 6337 is an uninteresting number.
Data storica: May 7th is the day in 1348 that Charles University in Prague (Universitas Carolina/Univerzita Karlova) is established as the first university in Central Europe.