Fatto generale: 1535 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1535 is an uninteresting number.
Trivia: 1535 is a boring number.
Data storica: March 14th is the day in 44 BC that Casca, Cicero and Cassius decided, in the night before the Assassination of Julius Caesar, that Mark Antony should stay alive.