Fatto matematico: 4398 is the number of subsets of {1, 2, 3, ... 18} that do not contain solutions to x + y = z.
Trivia: 4398 is an uninteresting number.
Data storica: January 15th is the day in 1782 that Superintendent of Finance Robert Morris goes before the U.S. Congress to recommend establishment of a national mint and decimal coinage.