86 (eighty-six) 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 85 and preceding 87.

In mathematics

86 is: *

nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotient ...

and a

noncototient In mathematics, a noncototient is a positive integer ''n'' that cannot be expressed as the difference between a positive integer ''m'' and the number of coprime integers below it. That is, ''m'' − φ(''m'') = ''n'', where � ...

. * the 25th distinct

semiprime In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so the semiprimes include the squares of prime numbers. Because there are infinitely many prime nu ...

and the 13th of the form (2×q). * an

Erdős–Woods number In number theory, a positive integer is said to be an Erdős–Woods number if it has the following property: there exists a positive integer such that in the sequence of consecutive integers, each of the elements has a non-trivial common factor ...

, since it is possible to find sequences of 86 consecutive integers such that each inner member shares a factor with either the first or the last member. * a

happy number 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 ...

and a

self number In number theory, a self number or Devlali number in a given number base b is a natural number that cannot be written as the sum of any other natural number n and the individual digits of n. 20 is a self number (in base 10), because no such combina ...

in base 10. It appears in the

Padovan sequence In number theory, the Padovan sequence is the sequence of integers ''P''(''n'') defined. by the initial values :P(0)=P(1)=P(2)=1, and the recurrence relation :P(n)=P(n-2)+P(n-3). The first few values of ''P''(''n'') are :1, 1, 1, 2, 2, 3, 4, 5 ...

, preceded by the terms 37, 49, 65 (it is the sum of the first two of these). It is

conjecture In mathematics, a conjecture is a conclusion or a proposition that is proffered on a tentative basis without proof. Some conjectures, such as the Riemann hypothesis (still a conjecture) or Fermat's Last Theorem (a conjecture until proven in 19 ...

d that 86 is the largest n for which the

decimal expansion A decimal representation of a non-negative real number is its expression as a sequence of symbols consisting of decimal digits traditionally written with a single separator: r = b_k b_\ldots b_0.a_1a_2\ldots Here is the decimal separator, is ...

of 2ⁿ contains no 0. 86 = (8 × 6 = 48) + (4 × 8 = 32) + (3 × 2 = 6). That is, 86 is equal to the sum of the numbers formed in calculating its multiplicative persistence.

In science

* 86 is 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 ...

radon Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colourless, odourless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through ...

. * There are 86 metals on the modern

periodic table The periodic table, also known as the periodic table of the (chemical) elements, is a rows and columns arrangement of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of ch ...

In other fields

*In American English, and particularly in the food service industry, 86 has become a slang term referring to an item being out of stock or discontinued, and by extension to a person no longer welcome on the premises. *The number of the French department

Vienne Vienne (; Poitevin-Saintongeais: ''Viéne'') is a landlocked department in the French region of Nouvelle-Aquitaine. It takes its name from the river Vienne. It had a population of 438,435 in 2019.postal code A postal code (also known locally in various English-speaking countries throughout the world as a postcode, post code, PIN or ZIP Code) is a series of letters or digits or both, sometimes including spaces or punctuation, included in a postal a ...

and in the name of a local basketball club,

Poitiers Basket 86 Poitiers Basket 86, also known as PB86 or simply Poitiers, is a French professional basketball team located in the city of Poitiers, in the Nouvelle-Aquitaine region, France. It competes in the French Pro B league. The club's home games are play ...

. * +86 is the

code for international direct dial Country calling codes or country dial-in codes are telephone number prefixes for reaching telephone subscribers in the networks of the member countries or regions of the International Telecommunication Union (ITU). The codes are defined by the ...

phone calls to

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. *An art gallery in Ventura, California, displaying art pieces from such artists

Billy Childish Billy Childish (born Steven John Hamper, 1 December 1959) is an English painter, author, poet, photographer, film maker, singer and guitarist. Since the late 1970s, Childish has been prolific in creating music, writing and visual art. He has le ...

Stacy Lande Stacy Lande is a contemporary lowbrow painter."Weirdo Deluxel Google Books/ref>"The Red Boxl Google Books/ref>La Luz de Jesus Gallery websit/ref> Biography Stacy Lande was born in Granada Hills, in the San Fernando Valley region of Los Angeles ...

and

Derek Hess Derek Hess is an American artist based in Cleveland, Ohio. His creative career grew largely out of his ability to express the emotion in the indie, hardcore, and metal scenes of the mid-1990s. From concert posters to politically charged fine art pi ...

, most of which include the number *86 hidden or overtly shown in the art, and some of which fall under the genre of lowbrow. *86 is the device number for a lockout relay function in

electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

electrical circuit protection schemes. *86 is often used in Japan as the nickname for the

Toyota AE86 The AE86 series of the Toyota Corolla Levin and Toyota Sprinter Trueno are small, front-engine/rear-wheel-drive models within the front-engine/front-wheel-drive fifth generation Corolla (E80) range—marketed by Toyota from 1983 to 1987 in cou ...

. * ''86'' is the name of a series of Japanese science fiction

light novels A light novel (, Hepburn: ''raito noberu'') is a style of young adult novel primarily targeting high school and middle school students. The term "light novel" is a ''wasei-eigo'', or a Japanese term formed from words in the English language ...

written by

Asato Asato is a female Japanese novelist. The pen name Asato Asato is a combination of her real name (Toru Asakura) and eighty-eight. Career Asato started writing novels just before she entered junior high school. She initially submitted her work to t ...

, later adapted as a manga and an anime.

Notes

{{DEFAULTSORT:86 (Number) Integers

In mathematics

In science

In other fields

See also

Notes