79 (seventy-nine) is the

natural number In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''Cardinal n ...

following 78 and preceding 80.

In mathematics

79 is: * An

odd Odd means unpaired, occasional, strange or unusual, or a person who is viewed as eccentric. Odd may also refer to: Acronym * ODD (Text Encoding Initiative) ("One Document Does it all"), an abstracted literate-programming format for describing X ...

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. Further ...

s. * The 22nd

prime number A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...

(between and ) * An isolated prime without a

twin prime A twin prime is a prime number that is either 2 less or 2 more than another prime number—for example, either member of the twin prime pair (41, 43). In other words, a twin prime is a prime that has a prime gap of two. Sometimes the term ''twin pr ...

, as 77 and 81 are composite. * The smallest prime number ''p'' for which the

real quadratic field In algebraic number theory, a quadratic field is an algebraic number field of degree two over \mathbf, the rational numbers. Every such quadratic field is some \mathbf(\sqrt) where d is a (uniquely defined) square-free integer different from 0 ...

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 circular prime is a prime number with the property that the number generated at each intermediate step when cyclically permuting its (base 10) digits will be prime. For example, 1193 is a circular prime, since 1931, 9311 and 3119 all are also p ...

. * A prime number that is also a

Gaussian prime In number theory, a Gaussian integer is a complex number whose real and imaginary parts are both integers. The Gaussian integers, with ordinary addition and multiplication of complex numbers, form an integral domain, usually written as \mathbf /ma ...

(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 remain ...

. * A

permutable prime A permutable prime, also known as anagrammatic prime, is a prime number which, in a given base, can have its digits' positions switched through any permutation and still be a prime number. H. E. Richert, who is supposedly the first to study th ...

, 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 algebraica ...

, 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 In number theory, a regular prime is a special kind of prime number, defined by Ernst Kummer in 1850 to prove certain cases of Fermat's Last Theorem. Regular primes may be defined via the divisibility of either class numbers or of Bernoulli num ...

. * 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 o ...

(with 73). * The ''n'' value of the

Wagstaff prime In number theory, a Wagstaff prime is a prime number of the form : where ''p'' is an odd prime. Wagstaff primes are named after the mathematician Samuel S. Wagstaff Jr.; the prime pages credit François Morain for naming them in a lecture at the ...

201487636602438195784363. * Similarly to how the decimal expansion of 1/ 89 gives Fibonacci numbers, 1/79 gives

Pell number In mathematics, the Pell numbers are an infinite sequence of integers, known since ancient times, that comprise the denominators of the closest rational approximations to the square root of 2. This sequence of approximations begins , , , , an ...

s, 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 Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

(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 A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

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 ''Live Seventy Nine'' is a 1980 live album by Hawkwind recorded on their Winter 1979 UK tour. It reached #15 on the UK album chart. This is a reconstituted Hawkwind with Brock, Bainbridge and King emerging from the dissolved Hawklords, joined ...

'', 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 hard ...

* 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 ...

or 1979 * The number of the

French department In the administrative divisions of France, the department (french: département, ) is one of the three levels of government under the national level ("territorial collectivities"), between the administrative regions and the communes. Ninety-s ...

Deux-Sèvres Deux-Sèvres () is a French department. ''Deux-Sèvres'' literally means "two Sèvres": the Sèvre Nantaise and the Sèvre Niortaise are two rivers which have their sources in the department. It had a population of 374,878 in 2019.

* 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