Fatto generale: 6444 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 6444 is the smallest number whose 5^{th} power starts with 5 identical digits.
Trivia: 6444 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: August 22nd is the day in 1875 that the Treaty of Saint Petersburg between Japan and Russia is ratified, providing for the exchange of Sakhalin for the Kuril Islands.