Hecho general: 13021 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 13021 is a boring number.
Trivia: 13021 is an uninteresting number.
Fecha histórica: August 25th is the day in 1894 that Kitasato Shibasaburō discovers the infectious agent of the bubonic plague and publishes his findings in The Lancet.