|Cardinal||one hundred and thirteen|
(one hundred and thirteenth)
113 is the 30th prime number, following 109 and preceding 127, a Sophie Germain prime, a Chen prime and a Proth prime as it is a prime number of the form 7 × 24 + 1. 113 is an Eisenstein prime with no imaginary part and real part of the form . In base 10, this prime is a primeval number, and a permutable prime with 131 and 311.
It is a highly cototient number and a centered square number. 355/113 approximates pi to six decimal places, with an error of less than 1/1133. This means that 113/355 approximates the reciprocal of pi.
- The fire emergency telephone number in Indonesia
- The medical emergency telephone number in Norway and Latvia
- The police emergency telephone number in Italy, Luxembourg, Slovenia and Vietnam
- The Argentina time telephone number
- The intelligence Agency telephone number in Iran
- 113 (band), a French hip hop group
One hundred [and] thirteen is also:
- The port number of the IDENT Internet protocol that helps identify the user of a particular TCP connection
- Cadmium-113m is a radioisotope and nuclear isomer with a halflife of 14.1 years
- The atomic number of an element temporarily called ununtrium.
- In enduro, it is regarded as an unlucky number to be given to a race entrant and is colloquially known as a "blind pew"
- The number of surat al-Falaq in the Qur'an.
- Psalms 113–118 constitute the Hallel, which is recited on the three great feasts, Passover, Weeks, and Tabernacles
- Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 134