|Cardinal||one hundred thirteen|
(one hundred thirteenth)
The number 113 (one hundred [and] thirteen) is used in many contexts.
- 113 is the natural number following 112 and preceding 114.
- It is the 30th prime number (following 109 and preceding 127), so it can only be divided by one and itself. 113 is 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 also 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.
- 113 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.
- 113 is the smallest positive integer that cannot be represented in the Four fours problem using standard rules.[clarification needed][dubious ]
- 113, 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
- 113, the atomic number of the element Nihonium
- Cadmium-113m, a radioisotope and nuclear isomer with a halflife of 14.1 years
- The fire emergency telephone number in Indonesia
- The intelligence agency telephone number in Iran
- The medical emergency telephone number in Latvia and Norway
- The police emergency telephone number in Italy, Luxembourg, Slovenia, and Vietnam
- The time telephone number in Argentina
- The mental health crisis hotline telephone number in the Netherlands
- 113 (band), a French hip hop group
- 113, the port number of the IDENT Internet protocol that helps identify the user of a particular TCP connection
- 113, in enduro, is regarded as an unlucky number to be given to a race entrant and is colloquially known as a "blind pew"
- "Sloane's A005384 : Sophie Germain primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- "Sloane's A109611 : Chen primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- "Sloane's A072857 : Primeval numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- "Sloane's A100827 : Highly cototient numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- "Sloane's A001844 : Centered square numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 134