General fact: 599 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 599 is the smallest number whose digits add to 23.
Trivia: 599 is a boring number.
Historical date: August 21st is the day in 1968 that James Anderson, Jr. posthumously receives the first Medal of Honor to be awarded to an African American U.S. Marine.