79 (number)

← 78 79 80 →
← 70 71 72 73 74 75 76 77 78 79 → List of numbers ; Integers ; ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	seventy-nine
Ordinal	79th; (seventy-ninth)
Factorization	prime
Prime	22nd
Divisors	1, 79
Greek numeral	ΟΘ´
Roman numeral	LXXIX
Binary	10011112
Ternary	22213
Senary	2116
Octal	1178
Duodecimal	6712
Hexadecimal	4F16

Last updated November 09, 2024

79 (seventy-nine) is the natural number following 78 and preceding 80.

In mathematics

79 is:

An odd number.
The smallest number that can not be represented as a sum of fewer than 19 fourth powers.
The 22nd prime number (between 73 and 83)
An isolated prime without a twin prime, as 77 and 81 are composite.^[1]
The smallest prime number p for which the real quadratic field Q[√p] has class number greater than 1 (namely 3).^[2]
A cousin prime with 83.
An emirp in base 10, because the reverse of 79, 97, is also a prime.^[3]
A Fortunate prime.^[4]
A circular prime.^[5]
A prime number that is also a Gaussian prime (since it is of the form 4n + 3).
A happy prime.^[6]
A Higgs prime.^[7]
A lucky prime.^[8]
A permutable prime, with ninety-seven.
A Pillai prime,^[9] because 23! + 1 is divisible by 79, but 79 is not one more than a multiple of 23.
A regular prime.^[10]
A right-truncatable prime, because when the last digit (9) is removed, the remaining number (7) is still prime.
A sexy prime (with 73).
The n value of the Wagstaff prime 201487636602438195784363.
Similarly to how the decimal expansion of 1/89 gives Fibonacci numbers, 1/79 gives Pell numbers, that is, ${\frac {1}{79}}=\sum _{n=1}^{\infty }{P(n)\times 10^{-(n+1)}}=0.0126582278\dots \ .$
A Leyland number of the second kind ^[11] and Leyland prime of the second kind,^[12] using 2 & 7 ( $2^{7}-7^{2}$ )

In science

The atomic number of the chemical element gold (Au) is 79.

In astronomy

Messier object 79 (M79), a magnitude 8.5 globular cluster in the constellation Lepus
New General Catalogue object 79 (NGC 79), a galaxy in the constellation Andromeda

In other fields

Live Seventy Nine , an album by Hawkwind
The years 79 BC, AD 79 or 1979
The number of the French department Deux-Sèvres
The ASCII code of the capital letter O

Related Research Articles

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References

↑ Sloane, N. J. A. (ed.). "SequenceA007510(Single (or isolated or non-twin) primes: Primes p such that neither p-2 nor p+2 is prime.)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved 2022-12-05.
↑ H. Cohen, A Course in Computational Algebraic Number Theory, GTM 138, Springer Verlag (1993), Appendix B2, p.507. The table lists fields by discriminant, which is 4p for Q[√p] when p is congruent to 3 modulo 4, as is the case for 79, so the entry appears at discriminant 316.
↑ "Sloane's A006567 : Emirps". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ "Sloane's A046066 : Fortunate primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ Numbers such that every cyclic permutation is a prime.
↑ "Sloane's A035497 : Happy primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ "Sloane's A007459 : Higgs' primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ "Sloane's A031157 : Numbers that are both lucky and prime". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ "Sloane's A063980 : Pillai primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ "Sloane's A007703 : Regular primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
↑ Sloane, N. J. A. (ed.). "SequenceA045575(Leyland numbers of the second kind)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
↑ Sloane, N. J. A. (ed.). "SequenceA123206(Leyland prime numbers of the second kind)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.

External links

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[1] Sloane, N. J. A. (ed.). "SequenceA007510(Single (or isolated or non-twin) primes: Primes p such that neither p-2 nor p+2 is prime.)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved 2022-12-05.

[2] H. Cohen, A Course in Computational Algebraic Number Theory, GTM 138, Springer Verlag (1993), Appendix B2, p.507. The table lists fields by discriminant, which is 4p for Q[√p] when p is congruent to 3 modulo 4, as is the case for 79, so the entry appears at discriminant 316.

[3] "Sloane's A006567 : Emirps". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[4] "Sloane's A046066 : Fortunate primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[5] Numbers such that every cyclic permutation is a prime.

[6] "Sloane's A035497 : Happy primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[7] "Sloane's A007459 : Higgs' primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[8] "Sloane's A031157 : Numbers that are both lucky and prime". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[9] "Sloane's A063980 : Pillai primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[10] "Sloane's A007703 : Regular primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.

[11] Sloane, N. J. A. (ed.). "SequenceA045575(Leyland numbers of the second kind)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.

[12] Sloane, N. J. A. (ed.). "SequenceA123206(Leyland prime numbers of the second kind)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.

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