11 (eleven) is an English number that lies between ten and twelve. It is a natural number and an odd integer. In mathematics, 11 is the smallest prime number that forms a cycle. In number theory, 11 is also known as a Heegner number.

In chemistry, 11 represents the atomic number of sodium. In music, 11 is the title of an album created by the Chinese band combination and the logic gate. In various fields, 11 holds different meanings such as Yao Ming’s jersey number, Singles’ Day, protagonists in animations and novels, and more.

11 is an odd number and a prime number. It is the smallest prime number among two-digit numbers and is also the atomic number of sodium. When counting from 0 to 10, a new cycle begins with 11.