21 is a number that comprises the sequence of digits 2 and 1 of the Arabic Numeral System—the most widely used numeral system in the world. The number 21 first appeared on Sesame Street in 1986 (when sponsor numbers below 2 and above 12 were first permitted). In total, the number 21 has sponsored two episodes, both of which first aired in the mid-1990s. It remained the highest number to sponsor an episode of Sesame Street for several years, until producers chose the number 40 as a special feature in Episode 4187 (the Season 40 (2009-2010) premiere).

Skits about 21 Edit

• Numberella
• Ernie's "12 and 21" poem

Previous number:	Next number:
20	40