Fatto matematico: 8669 is the maximum value of n so that there exist 5 denominations of stamps so that every postage from 1 to n can be paid for with at most 18 stamps.
Trivia: 8669 is a boring number.
Data storica: September 25th is the day in 1978 that PSA Flight 182, a Boeing 727-214, collides in mid-air with a Cessna 172 and crashes in San Diego, California, resulting in the deaths of 144 people.