Hecho general: 6726 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 6726 is the 10^{th} Pell-Lucas number.
Trivia: 6726 is an uninteresting number.
Fecha histórica: May 31st is the day in 1970 that the Ancash earthquake causes a landslide that buries the town of Yungay, Peru; more than 47,000 people are killed.