Fait général: 6603 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 6603 is a number whose square and cube use different digits.
Culture générale: 6603 is an uninteresting number.
Date historique: January 28th is the day in 1958 that the Lego company patents the design of its Lego bricks, still compatible with bricks produced today.