55 (fifty-five) 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 54 and preceding 56.

Mathematics

55 is *a

triangular number A triangular number or triangle number counts objects arranged in an equilateral triangle. Triangular numbers are a type of figurate number, other examples being square numbers and cube numbers. The th triangular number is the number of dots in ...

(the sum of the consecutive numbers 1 to 10), and a

doubly triangular number In mathematics, the doubly triangular numbers are the numbers that appear within the sequence of triangular numbers, in positions that are also triangular numbers. That is, if T_n=n(n+1)/2 denotes the nth triangular number, then the doubly triangul ...

. *the 10th Fibonacci number. It is the largest Fibonacci number to also be a triangular number. * a

square pyramidal number In mathematics, a pyramid number, or square pyramidal number, is a natural number that counts the number of stacked spheres in a pyramid with a square base. The study of these numbers goes back to Archimedes and Fibonacci. They are part of a broa ...

(the sum of the squares of the

integer An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign (−1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language ...

s 1 to 5) as well as a

heptagonal number A heptagonal number is a figurate number that is constructed by combining heptagons with ascending size. The ''n''-th heptagonal number is given by the formula :H_n=\frac. The first few heptagonal numbers are: : 0, 1, 7, 18, 34, 55, 81, 112, ...

, and a

centered nonagonal number A centered nonagonal number (or centered enneagonal number) is a centered figurate number that represents a nonagon with a dot in the center and all other dots surrounding the center dot in successive nonagonal layers. The centered nonagonal n ...

. *In base 10, it is a Kaprekar number.

Science

*The atomic number of

caesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that a ...

Astronomy

* Messier object M55, a magnitude 7.0 globular cluster in the constellation Sagittarius *The

New General Catalogue The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and ...

object NGC 55, a magnitude 7.9 barred spiral galaxy in the constellation

Sculptor Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

Music

* The name of a song by

Kasabian Kasabian ( ) are an English rock band formed in Leicester in 1997 by lead vocalist Tom Meighan, guitarist and occasional vocalist Sergio Pizzorno, guitarist Chris Karloff, and bassist Chris Edwards. Drummer Ian Matthews joined in 2004. Karlof ...

. The song was released as a B side to ''Club Foot'' and was recorded live when the band performed at London's Brixton Academy. * "55", a song by

Mac Miller Malcolm James McCormick (January 19, 1992 – September 7, 2018), known professionally as Mac Miller, was an American rapper and record producer. Miller began his career in Pittsburgh's hip hop scene in 2007, at the age of fifteen. In 2010, h ...

* "

I Can't Drive 55 "I Can't Drive 55" is the lead single and first track from Sammy Hagar's eighth studio album ''VOA'' in 1984. Perpetuated by a very successful music video, it became a concert staple that continued throughout Hagar's tours as a member of Van Hal ...

", a song by Sammy Hagar * "

Ol' '55 "Ol' '55" is a song by American musician Tom Waits. It is the opening track and lead single from Waits' debut studio album, '' Closing Time'', released in March 1973 on Asylum Records. Written by Waits and produced by Jerry Yester, "Ol' '55" was ...

", a song by Tom Waits * Ol' 55 (band), an Australian rock band. *

Primer 55 Primer 55 was an American nu metal band which formed in Memphis, Tennessee in 1997. The name originated from the combination of Primer, meaning "something that's unfinished", and 55, which refers to Interstate 55, "the road that drugs run on to ...

an American band * ''Station 55'', an album released in 2005 by Cristian Vogel * ''

55 Cadillac ''55 Cadillac'' is the fourth studio album by American musician Andrew W.K., released in the US on September 1, 2009, in the UK on September 7, and on September 8, 2009 through Ecstatic Peace! on vinyl format and W.K.'s own record label, Skyscrape ...

'', an album by Andrew W.K.

Transportation

*In the United States, the National Maximum Speed Law prohibited speed limits higher than from 1974 to 1987

Film

* ''

55 Days at Peking ''55 Days at Peking'' is a 1963 American epic historical war film dramatizing the siege of the foreign legations' compounds in Peking (now known as Beijing) during the Boxer Rebellion, which took place in China from 1899 to 1901. It was produc ...

'' a film starring Charlton Heston and David Niven

Years

AD 55 AD 55 ( LV) was a common 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 Caesar and Vetus (or, less frequently, year 808 ''Ab urbe condita''). Th ...

55 BC __NOTOC__ Year 55 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Crassus and Pompey (or, less frequently, year 699 ''Ab urbe condita''). The denomination 55 BC for this year has been us ...

1755 Events January–March * January 23 (O. S. January 12, Tatiana Day, nowadays celebrated on January 25) – Moscow University is established. * February 13 – The kingdom of Mataram on Java is divided in two, creating the ...

1855 Events January–March * January 1 – Ottawa, Ontario, is incorporated as a city. * January 5 – Ramón Castilla begins his third term as President of Peru. * January 23 ** The first bridge over the Mississippi River opens ...

1955 Events January * January 3 – José Ramón Guizado becomes president of Panama. * January 17 – , the first nuclear-powered submarine, puts to sea for the first time, from Groton, Connecticut. * January 18– 20 – Battle of Yijian ...

Other uses

*''

Gazeta 55 ''Gazeta 55'' ( en, Newspaper 55) is an Albanian language newspaper published in Tirana, Albania. The newspaper is a politically unaffiliated daily, with nine reporters on staff records. The tabloid's owner is Fahri Balliu, an Albanian businessma ...

'', an Albanian newspaper *

Agitation and Propaganda against the State Constitution 55, or Agitation and Propaganda against the State ( sq, Agjitacion dhe Propagandë kundër shtetit), was a criminal offence in Communist Albania. This law was used from 1945 until 1991 and was part of the Constitution of the People's S ...

, also known as Constitution law 55, a law during Communist Albania. *The code for international direct dial phone calls to

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

55-gallon drum A drum (also called a barrel) is a cylinder (geometry), cylindrical shipping container used for shipping bulk cargo. Drums can be made of steel, dense paperboard (commonly called a fiber drum), or plastic, and are generally used for the transpor ...

for containing oil, etc. *The Élysée, the official residency of the

French Republic France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

president, which address is 55

rue du Faubourg-Saint-Honoré ''Ruta graveolens'', commonly known as rue, common rue or herb-of-grace, is a species of '' Ruta'' grown as an ornamental plant and herb. It is native to the Balkan Peninsula. It is grown throughout the world in gardens, especially for its bl ...

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

References

{{Integers, zero Integers