Fatto generale: 99643 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 99643 is an unremarkable number.
Trivia: 99643 is an unremarkable number.
Data storica: October 23rd is the day in 2011 that a powerful 7.2 magnitude earthquake strikes Van Province, Turkey, killing 582 people and injuring thousands.