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 power In arithmetic and algebra, the fourth power of a number ''n'' is the result of multiplying four instances of ''n'' together. So: :''n''4 = ''n'' × ''n'' × ''n'' × ''n'' Fourth powers are also formed by multiplying a number by its cube. Furthe ...

s. * The 22nd prime number (between and ) * An isolated prime without a twin prime, as 77 and 81 are composite. * The smallest prime number ''p'' for which the real quadratic field Q[] has Ideal class group, class number greater than 1 (namely 3). * A cousin prime with 83. * An emirp, because the reverse of 79, 97 (number), 97, is also a prime. * A Fortunate prime. * A circular prime. * A prime number that is also a Gaussian prime (since it is of the form ). * A

happy prime In number theory, a happy number is a number which eventually reaches 1 when replaced by the sum of the square of each digit. For instance, 13 is a happy number because 1^2+3^2=10, and 1^2+0^2=1. On the other hand, 4 is not a happy number because ...

. * A

Higgs prime A Higgs prime, named after Denis Higgs, is a prime number with a totient (one less than the prime) that evenly divides the square of the product of the smaller Higgs primes. (This can be generalized to cubes, fourth powers, etc.) To put it algebrai ...

. * A

lucky prime In number theory, a lucky number is a natural number in a set which is generated by a certain "sieve". This sieve is similar to the Sieve of Eratosthenes that generates the primes, but it eliminates numbers based on their position in the remaini ...

. * A permutable prime, with ninety-seven. * A

Pillai prime In number theory, a Pillai prime is a prime number ''p'' for which there is an integer ''n'' > 0 such that the factorial of ''n'' is one less than a multiple of the prime, but the prime is not one more than a multiple of ''n''. To put it algebraical ...

, because 23 ! + 1 is

divisible In mathematics, a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible or evenly divisible by ...

by 79, but 79 is not one more than a multiple of 23. * A regular prime. * A right-truncatable prime, because when the last digit (9) is removed, the remaining number (7) is still prime. * A

sexy prime In number theory, sexy primes are prime numbers that differ from each other by 6. For example, the numbers 5 and 11 are both sexy primes, because both are prime and . The term "sexy prime" is a pun stemming from the Latin word for six: . If ...

(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=\sum_^\infty=0.0126582278\dots\ .

* A Leyland number of the second kind.

In science

* The

atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...

of the

chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...

gold (Au) is 79. Lake Tahoe AleWorX - 2021-10-19 - Sarah Stierch 01

In astronomy

* Messier object 79 (M79), a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

8.5 globular cluster in the constellation

Lepus Hares and jackrabbits are mammals belonging to the genus ''Lepus''. They are herbivores, and live solitarily or in pairs. They nest in slight depressions called forms, and their young are able to fend for themselves shortly after birth. The gen ...

* New General Catalogue object 79 (NGC 79), a

galaxy A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

in the constellation Andromeda

In other fields

* '' Live Seventy Nine'', an album by

Hawkwind Hawkwind are an English rock band known as one of the earliest space rock groups. Since their formation in November 1969, Hawkwind have gone through many incarnations and have incorporated many different styles into their music, including har ...

* The years

79 BC __NOTOC__ Year 79 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Vatia Isauricus and Claudius Pulcher (or, less frequently, year 675 ''Ab urbe condita''). The denomination 79 BC for this ...

AD 79 __NOTOC__ AD 79 ( LXXIX) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Titus and Vespasianus (or, less frequently, year 832 ''Ab urb ...

1979 Events January * January 1 ** United Nations Secretary-General Kurt Waldheim heralds the start of the ''International Year of the Child''. Many musicians donate to the ''Music for UNICEF Concert'' fund, among them ABBA, who write the song ...

* The number of the French department Deux-Sèvres * The

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...

code of the capital letter O

References

{{DEFAULTSORT:79 (Number) Integers