Hecho general: 5904 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 5904 is an unremarkable number.
Trivia: 5904 is an unremarkable number.
Fecha histórica: February 29th is the day in 1504 that Christopher Columbus uses his knowledge of a lunar eclipse that night to convince Native Americans to provide him with supplies.