Hecho matemático: 7668 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 7668 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fecha histórica: December 28th is the day in 1895 that Wilhelm Röntgen publishes a paper detailing his discovery of a new type of radiation, which later will be known as x-rays.