Fait général: 16820 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 16820 is an unremarkable number.
Culture générale: 16820 is an uninteresting number.
Date historique: January 18th is the day in 1969 that United Airlines Flight 266 crashes into Santa Monica Bay killing all 32 passengers and six crew members.