Fatto matematico: 2394 is the smallest value of n for which n and 7n together use each digit 1-9 exactly once.
Trivia: 2394 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: July 21st is the day in 1997 that the fully restored USS Constitution (aka Old Ironsides) celebrates her 200th birthday by setting sail for the first time in 116 years.