General fact: 16 is the number of teams that qualified for the finals of the FIFA World Cup from 1934 through 1978 (although for various reasons, only 15 competed in the 1938 and 1950 finals).
Mathematical fact: 16 is the hexadecimal system, a common number system used in computer programming, uses 16 digits where the last 6 are usually represented by letters: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F.
Trivia: 16 is the number of personality types in the Myers-Briggs classification system.
Historical date: January 16th is the day in 1991 that the Coalition Forces go to war with Iraq, beginning the Gulf War (U.S. Time).