General fact: 840 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 840 is the smallest number divisble by 1 through 8.
Trivia: 840 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Historical date: April 19th is the day in 65 that the freedman Milichus betrayed Piso’s plot to kill the Emperor Nero and all the conspirators were arrested.