161 (one hundred ndsixty-one) 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 ...

following 160 and preceding 162.

In mathematics

* 161 is the sum of five consecutive

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 ...

s: 23, 29, 31, 37, and 41 * 161 is a hexagonal pyramidal number. * 161 is a

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 ...

. Since its prime factors 7 and 23 are both

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 ...

s, 161 is a

Blum integer In mathematics, a natural number ''n'' is a Blum integer if is a semiprime for which ''p'' and ''q'' are distinct prime numbers congruent to 3 mod 4.Joe Hurd, Blum Integers (1997), retrieved 17 Jan, 2011 from http://www.gilith.com/research/tal ...

. * 161 is a palindromic number * is a commonly used rational approximation of the

square root of 5 The square root of 5 is the positive real number that, when multiplied by itself, gives the prime number 5. It is more precisely called the principal square root of 5, to distinguish it from the negative number with the same property. This numbe ...

and is the closest fraction with denominator <300 to that number.

In the military

* was a

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...

Type

T2 tanker The T2 tanker, or T2, was a class of oil tanker constructed and produced in large quantities in the United States during World War II. Only the T3 tankers were larger "navy oilers" of the period. Some 533 T2s were built between 1940 and the end of ...

during World War II * was a U.S. Navy during World War II * was a U.S. Navy ''Trefoil''-class concrete barge during World War II * was a U.S. Navy during World War II * was a U.S. Navy during World War II * was a U.S. Navy during World War II * was a U.S. Navy wooden

yacht A yacht is a sailing or power vessel used for pleasure, cruising, or racing. There is no standard definition, though the term generally applies to vessels with a cabin intended for overnight use. To be termed a , as opposed to a , such a pleasu ...

during World War I * was a U.S. Navy during World War II * was a U.S. Navy ''Achomawi''-class fleet ocean tug following World War II * was a U.S. Navy fourth-group S-class submarine between 1920 and 1931 * is a fictional U.S. Navy

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...

submarine featured in the 1996 film ''

Down Periscope ''Down Periscope'' is a 1996 American military comedy submarine film directed by David S. Ward, produced by Robert Lawrence, and starring Kelsey Grammer, Lauren Holly, and Rob Schneider along with Bruce Dern, Harry Dean Stanton, William H. Macy, ...

'' * The

161st Intelligence Squadron The 161st Intelligence Squadron (161 IS) is a unit of the 184th Wing of the Kansas Air National Guard stationed at McConnell Air Force Base, Wichita, Kansas. The 161st is a non-flying squadron operating the Distributed Common Ground System T ...

unit of the

Kansas Air National Guard The Kansas Air National Guard (KS ANG) is the aerial militia of the State of Kansas, United States of America. It is, along with the Kansas Army National Guard, an element of the Kansas National Guard. As state militia units, the units in the K ...

. Its parent unit is the

184th Intelligence Wing The 184th Wing (184 WG) is a unit of the Kansas Air National Guard, stationed at McConnell Air Force Base, Wichita, Kansas. If activated to federal service, the Wing is gained by the United States Sixteenth Air Force. The 127th Command and Con ...

In music

* The Bose 161 Speaker System (2001) * The Kay K-161 ThinTwin guitar

In transportation

* MTA Maryland commuter bus 161 *

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

Bus Route 161 * London Bus route 161

In other fields

161 is also: * The year AD 161 or 161 BC * 161 AH is a year in the

Islamic calendar The Hijri calendar ( ar, ٱلتَّقْوِيم ٱلْهِجْرِيّ, translit=al-taqwīm al-hijrī), also known in English as the Muslim calendar and Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 ...

that corresponds to 777 – 778 CE * 161 Athor is an M-type

Main belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

asteroid * E.161 is an

ITU-T The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Comm ...

assigns letters to the 12-key telephone keypad * Fiorina Fury 161 is a foundry facility and penal colony from the film

Alien 3 ''Alien 3'' (stylized as ''A''LIEN³) is a 1992 American science fiction horror film directed by David Fincher and written by David Giler, Walter Hill, and Larry Ferguson, from a story by Vincent Ward. It stars Sigourney Weaver, reprising her ...

* 161 is used by

Anti Fascist Action Anti-Fascist Action (AFA) was a militant Anti-fascism, anti-fascist organisation, founded in the UK in 1985 by a wide range of anti-racist and anti-fascist organisations. It was active in fighting far-right organisations, particularly the Briti ...

as a code for AFA (A=1, F=6, by order of the alphabet), sometimes used in 161>88 (88 is code for Heil Hitler among

neo-nazis Neo-Nazism comprises the post–World War II militant, social, and political movements that seek to revive and reinstate Nazi ideology. Neo-Nazis employ their ideology to promote hatred and racial supremacy (often white supremacy), attack ...

, as H=8)

External links

Number Facts and Trivia: 161

The Number 161

References

{{DEFAULTSORT:161 (Number) Integers