Hecho matemático: 6556 is the largest palindrome that can be made using 5 digits and the 4 arithmetic operations.
Trivia: 6556 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fecha histórica: December 12th is the day in 1408 that the Order of the Dragon a monarchical chivalric order is created by Sigismund of Luxembourg, then King of Hungary.