Fatto generale: 12535 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 12535 is an unremarkable number.
Trivia: 12535 is an uninteresting number.
Data storica: April 26th is the day in 1478 that the Pazzi attack Lorenzo de' Medici and kill his brother Giuliano during High Mass in the Duomo of Florence.