All NFL teams wore #21 on their helmets in Week 13 of 2007, to honor Sean Taylor, the Redskins star who was killed. Some, but not all, NFL teams continued wearing the number for the rest of the season.
there is 21 teams in the premier league if not there is either 22,21or20
21
21
If you don't believe me you should Ive counted all the teams from Brazil it's 21
In the 1980 NHL season, each of the 21 teams played 80 games.
Presuming you mean so far this season, the remaining undefeated teams are the Saints, Vikings, Broncos and Colts (as of 10-21-09).
The factors of 21 are :1,3,7,21
Several NFL teams are honoring the late Sean Taylor, #21 on the Washington Redskins, after he was killed in a botched burglary at his home in Miami.
21.
4 factors they are 1,3,7 and 21
Many people..........