113 (number)

← 112 113 114 →
← 110 111 112 113 114 115 116 117 118 119 → List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	one hundred thirteen
Ordinal	113th (one hundred and thirteenth)
Factorization	prime
Prime	30th
Divisors	1, 113
Roman numeral	CXIII
Binary	11100012
Ternary	110123
Quaternary	13014
Quinary	4235
Senary	3056
Octal	1618
Duodecimal	9512
Hexadecimal	7116
Vigesimal	5D20
Base 36	3536

The number 113 (pronounced one hundred thirteen) is used in many contexts.

Mathematics

• 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,^[1] a Chen prime^[2] 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 $3n-1$. In base 10, this prime is a primeval number,^[3] and a permutable prime with 131 and 311.

• 113 is a highly cototient number^[4] and a centered square number.^[5]
• 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.

Religion

• 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

Science

• 113, the atomic number of the element Nihonium
• Cadmium-113m, a radioisotope and nuclear isomer with a halflife of 14.1 years

Telephony

113 is:

• 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

Other uses

• 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"

See also

• List of highways numbered 113
• List of oldest people
• M113 (disambiguation)
• National longevity recordholders
• A113

References

1. "Sloane's A005384 : Sophie Germain primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
2. "Sloane's A109611 : Chen primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
3. "Sloane's A072857 : Primeval numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
4. "Sloane's A100827 : Highly cototient numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
5. "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