Hecho matemático: 55221 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 55221 is an unremarkable number.
Fecha histórica: March 10th is the day in 2005 that Tung Chee Hwa resigns from his post as the first Chief Executive of Hong Kong after widespread public dissatisfaction of his tenure.