Fatto generale: 20788 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 20788 is an unremarkable number.
Trivia: 20788 is a boring number.
Data storica: November 29th is the day in 1781 that the crew of the British slave ship Zong murders 133 Africans by dumping them into the sea to claim insurance.