Fatto generale: 1606 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1606 is the number of strongly connected digraphs with 4 vertices.
Trivia: 1606 is a boring number.
Data storica: May 24th is the day in 1976 that the Judgement of Paris takes place in France, launching California as a worldwide force in the production of quality wine.