83 (number)

← 82 83 84 →
← 80 81 82 83 84 85 86 87 88 89 → List of numbers Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	eighty-three
Ordinal	83rd (eighty-third)
Factorization	prime
Prime	23rd
Divisors	1, 83
Greek numeral	ΠΓ´
Roman numeral	LXXXIII, lxxxiii
Binary	10100112
Ternary	100023
Senary	2156
Octal	1238
Duodecimal	6B12
Hexadecimal	5316

83 (eighty-three) is the natural number following 82 and preceding 84.

In mathematics

83 is:

• the sum of three consecutive primes (23 + 29 + 31).
• the sum of five consecutive primes (11 + 13 + 17 + 19 + 23).
• the 23rd prime number, following 79 (of which it is also a cousin prime) and preceding 89.
• a Sophie Germain prime. ^[1]
• a safe prime. ^[2]
• a Chen prime. ^[3]
• an Eisenstein prime with no imaginary part and real part of the form 3n − 1.
• a highly cototient number. ^[4]
• the number of primes that are right-truncatable. ^[5]
• a super-prime, because 23 is prime.

In other fields

• The eighth letter of the alphabet is H and the third letter is C, thus 83 stands for "Heil Christ," a greeting used by organizations that consider themselves also to be Christian. ^[6]
• An emoticon based on :3 with wide-open eyes.

References

1. "Sloane's A005384 : Sophie Germain primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
2. "Sloane's A005385 : Safe primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
3. "Sloane's A109611 : Chen primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
4. "Sloane's A100827 : Highly cototient numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
5. Sloane, N. J. A. (ed.). "SequenceA024770(Right-truncatable primes: every prefix is prime)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
6. "Hate Number Symbols: 83 - From A Visual Database of Extremist Symbols, Logos and Tattoos". Archived from the original on 2007-09-11. Retrieved 2007-09-24.