Hecho general: 266 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 266 is the Stirling number of the second kind S(8,6).
Trivia: 266 is an unremarkable number.
Fecha histórica: September 22nd is the day in 1991 that the Dead Sea Scrolls are made available to the public for the first time by the Huntington Library.