Hecho general: 21745 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 21745 is an unremarkable number.
Trivia: 21745 is an unremarkable number.
Fecha histórica: July 14th is the day in 1769 that an expedition led by Gaspar de Portolà establishes a base in California and sets out to find the Port of Monterey (now Monterey, California).