Fatto matematico: 4380 is the number of ways to place 2 non-attacking bishops on a 10×10 chessboard.
Trivia: 4380 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: December 28th is the day in 1972 that Kim Il-sung, already Prime Minister of North Korea and General Secretary of the Workers' Party of Korea, became the first President of North Korea.