Fatto matematico: 4890 is a narcissistic number in base 5.
Trivia: 4890 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: May 21st is the day in 2010 that JAXA, the Japan Aerospace Exploration Agency, launches the solar-sail spacecraft IKAROS aboard an H-IIA rocket.