240 (two hundred ndforty) 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 239 and preceding 241.

In mathematics

240 is: *a

semiperfect number In number theory, a semiperfect number or pseudoperfect number is a natural number ''n'' that is equal to the sum of all or some of its proper divisors. A semiperfect number that is equal to the sum of all its proper divisors is a perfect number. ...

. *a concatenation of two of its proper divisors. *a

highly composite number __FORCETOC__ A highly composite number is a positive integer with more divisors than any smaller positive integer has. The related concept of largely composite number refers to a positive integer which has at least as many divisors as any smaller ...

since it has 20 divisors total (1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 40, 48, 60, 80, 120, and 240), more than any previous number. *a

refactorable number A refactorable number or tau number is an integer ''n'' that is divisible by the count of its divisors, or to put it algebraically, ''n'' is such that \tau(n)\mid n. The first few refactorable numbers are listed in as : 1, 2, 8, 9, 12, 18, ...

or tau number, since it has 20 divisors and 20 divides 240. *a

highly totient number A highly totient number k is an integer that has more solutions to the equation \phi(x) = k, where \phi is Euler's totient function, than any integer below it. The first few highly totient numbers are 1, 2, 4, 8, 12, 24, 48, 72, 144, 240, ...

, since it has 31 totient answers, more than any previous integer. *a

pronic number A pronic number is a number that is the product of two consecutive integers, that is, a number of the form n(n+1).. The study of these numbers dates back to Aristotle. They are also called oblong numbers, heteromecic numbers,. or rectangular number ...

since it can be expressed as the product of two consecutive integers, 15 and 16. *palindromic in bases 19 (CC₁₉), 23 (AA₂₃), 29 (88₂₉), 39 (66₃₉), 47 (55₄₇) and 59 (44₅₉). *a

Harshad number In mathematics, a harshad number (or Niven number) in a given number base is an integer that is divisible by the sum of its digits when written in that base. Harshad numbers in base are also known as -harshad (or -Niven) numbers. Harshad numbers ...

in bases 2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15 (and 73 other bases). *the

aliquot sum In number theory, the aliquot sum ''s''(''n'') of a positive integer ''n'' is the sum of all proper divisors of ''n'', that is, all divisors of ''n'' other than ''n'' itself. That is, :s(n)=\sum\nolimits_d. It can be used to characterize the prime ...

of 120 and 57121. *part of the 12161-aliquot tree. The aliquot sequence starting at 120 is: 120, 240, 504, 1056, 1968, 3240, 7650, 14112, 32571, 27333, 12161, 1, 0. 240 is the smallest number that can be expressed as a sum of consecutive primes in three different ways: 240 = 113 + 127 = 53 + 59 + 61 + 67 = 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43. ''E''₈ has 240

roots A root is the part of a plant, generally underground, that anchors the plant body, and absorbs and stores water and nutrients. Root or roots may also refer to: Art, entertainment, and media * ''The Root'' (magazine), an online magazine focusing ...

. There are 240 distinct solutions of the

Soma cube The Soma cube is a solid dissection puzzle invented by Danish polymath Piet Hein in 1933 during a lecture on quantum mechanics conducted by Werner Heisenberg. Seven pieces made out of unit cubes must be assembled into a 3×3×3 cube. The pie ...

puzzle.

In other fields

240 is: * A common

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...

in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

before conversion to 230 V standard. * In pre-

decimal The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral ...

British currency Sterling (abbreviation: stg; Other spelling styles, such as STG and Stg, are also seen. ISO 4217, ISO code: GBP) is the currency of the United Kingdom and nine of #Crown Dependencies and British Overseas Territories, its associated territori ...

, the number of pence in a pound until 1971. * A

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

level of 240 and above is considered high risk. * The model number of the

Convair 240 The Convair CV-240 is an American airliner that Convair manufactured from 1947 to 1954, initially as a possible replacement for the ubiquitous Douglas DC-3. Featuring a more modern design with cabin pressurization, the 240 series made some inro ...

. * The year A.D. 240 or 240 BC. *

Datsun 240Z The Nissan S30 (sold in Japan as the Nissan Fairlady Z and in other markets as the Datsun 240Z, then later as the 260Z and 280Z) is the first generation of Z GT 3-door two-seat coupés, produced by Nissan Motors, Ltd. of Japan from 1969 until ...

* Mercedes 240D *

Nissan 240SX The Nissan 240SX is a sports compact car that was introduced to the North American market by Nissan in 1989 for the 1990 model year. It replaced the outgoing 200SX (S12) model. Most of the 240SXs were equipped with the 2.4-liter inline 4 engi ...

Volvo 240 __NOTOC__ Year 240 ( CCXL) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Sabinus and Venustus (or, less frequently, year 993 ''Ab ...

* An

area code A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, rea ...

overlay of the 301 area code in western

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

. * The famous skit by the sketch comedy group

The State A state is a centralized political organization that imposes and enforces rules over a population within a territory. There is no undisputed definition of a state. One widely used definition comes from the German sociologist Max Weber: a "stat ...

is entitled "$240 Worth of Pudding" * .240 Weatherby Magnum, rifle cartridge * 2-4-0, a

Whyte notation Whyte notation is a classification method for steam locomotives, and some internal combustion locomotives and electric locomotives, by wheel arrangement. It was devised by Frederick Methvan Whyte, and came into use in the early twentieth cen ...

classification of

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

* The top speed, in kilometers per hour, of the fastest roller coaster in the world,

Formula Rossa Formula Rossa (Arabic: فورمولا روسا) is a launched roller coaster located at Ferrari World in Abu Dhabi, United Arab Emirates. Manufactured by Intamin and opened in 2010, it is the world's fastest roller coaster, featuring a maximum s ...

References

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