Fatto generale: 12405 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 12405 is an unremarkable number.
Trivia: 12405 is an unremarkable number.
Data storica: December 17th is the day in 1819 that Simón Bolívar declares the independence of the Republic of Gran Colombia in Angostura (now Ciudad Bolívar in Venezuela).