Fatto generale: 1609 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1609 is the smallest number whose square contains 4 consecutive 8's.
Trivia: 1609 is a boring number.
Data storica: May 27th is the day in 1968 that the meeting of the Union Nationale des Étudiants de France (National Union of the Students of France) takes place.