Hecho general: 20409 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 20409 is a boring number.
Trivia: 20409 is an uninteresting number.
Fecha histórica: November 16th is the day in 1988 that the Supreme Soviet of the Estonian Soviet Socialist Republic declares that Estonia is "sovereign" but stops short of declaring independence.