Fatto matematico: 879 is a number n whose 5^{th} root has a decimal part that begins with the digits of n.
Trivia: 879 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: May 28th is the day in 585 BC that a solar eclipse occurs while Alyattes is battling Cyaxares in the Battle of the Eclipse, leading to a truce.