Fatto matematico: 20405 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 20405 is an unremarkable number.
Data storica: November 12th is the day in 1996 that a Saudi Arabian Airlines Boeing 747 and a Kazakh Ilyushin Il-76 cargo plane collide in mid-air near New Delhi, killing 349.