General fact: 6446 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 6446 is an uninteresting number.
Trivia: 6446 is an unremarkable number.
Historical date: August 24th is the day in 2006 that the International Astronomical Union (IAU) redefines the term "planet" such that Pluto is now considered a Dwarf Planet.