General fact: 538 is the total number of votes in the Electoral College of the United States.
Mathematical fact: 538 is the 10^{th} open meandric number.
Trivia: 538 is the total number of votes in the Electoral College of the United States.
Historical date: June 21st is the day in 1982 that John Hinckley is found not guilty by reason of insanity for the attempted assassination of U.S. President Ronald Reagan.