101 (number)

101 (one hundred [and] one) is the natural number following 100 and preceding 102. In British English it is always "one hundred and one", in American English it is pronounced "one hundred one", or "one oh one" in both.

Template:Numbers 100s
Cardinal	101 one hundred [and] one
Ordinal	101st one hundred [and] first
Factorization	prime
Roman numeral	CI
Binary	1100101
Hexadecimal	65

In mathematics

101 is the 26th prime number and a palindromic number (therefore also a palindromic prime). The next prime is 103, with which it comprises a twin prime (making 101 a Chen prime). Because the period length of its reciprocal is unique among primes, 101 is a unique prime. 101 is an Eisenstein prime with no imaginary part and real part of the form $3n-1$.

101 is the sum of five consecutive primes (13 + 17 + 19 + 23 + 29). Given 101, the Mertens function returns 0. 101 is the fifth alternating factorial.

101 is a centered decagonal number.

For a 3-digit number in base 10, this number has a relatively simple divisibility test. The number is split into groups of four, starting with the rightmost four, and added up to produce a 4-digit number. If this 4-digit number is of the form 1000a + 100b + 10a + b (where a and b are integers from 0 to 9), such as 3232 or 9797, or of the form 100b + b, such as 707 and 808, then the number is divisible by 101. This might not be as simple as the divisibility tests for numbers like 3 and 5, and it might not be terribly practical, but it is simpler than the divisibility tests for other 3-digit numbers.

On the seven-segment display of a calculator, 101 is both a strobogrammatic prime and a dihedral prime.

In science

• The atomic number of mendelevium, an actinide.
• In mineralogy, a Miller index of 101 is a crystal face that crosses the horizontal axis (a) and 3d vertical axis (c) but does not cross the 2d vertical axis (b).

In astronomy

• The Messier object M101, a magnitude 8.5 spiral galaxy in the constellation Ursa Major, also known as the Pinwheel Galaxy
• The New General Catalogue object NGC101, a magnitude 12.9 spiral galaxy in the constellation Sculptor
• The Asteroid 101 Helena.

In other fields

101 is also:

• An introduction or basic overview to a topic. By extension, it is informally used elsewhere to indicate things that are meant for beginners, or a crash course, i.e. User talk:Help101.
• The year AD 101 or 101 BC
• A beginning-level or basic course number taught at colleges and universities in Australia, Canada, South Africa, and the United States. An example would be English 101, which may be a remedial English. At universities with four-digit course numbers, the equivalent course number is 1001 or 1010. This usage is not common in the United Kingdom
• U.S. Route 101 runs from California to Washington
• In DisneySpeak, a ride breakdown in a disney theme park (an indirect reference to the US Route 101)
• The emergency telephone number for the police in Argentina.
• The emergency telephone number for the police in Belgium.
• The emergency telephone number for medical emergencies in Israel
• The emergency telephone number for the fire brigade in India.
• The Single Non-Emergency Number (SNEN), a new flat-rate telephone number being rolled out across the United Kingdom, intended as an easy to remember number, for non emergency calls to the police on occasions when dialing 999 is not appropriate. (official site)
• 101st kilometre, a condition of release from the Gulag in the Soviet Union
• The (minimum) number of keys on a standard computer keyboard.
• Unit 101 of the Israeli Defense Forces.
• The 101st Airborne Division (Air Assault)—nicknamed the “Screaming Eagles”—is an airborne division of the United States Army primarily trained for air assault operations
• For new (US) checking accounts, the default number for the first check.
• STS-101 Space Shuttle Atlantis mission launched May 19, 2000
• The Orbiter Vehicle Designation for Shuttle Enterprise
• Land Rover 101 Forward Control
• The trick-taking card game 101, in which the seniority of cards is: Five, Jack, Joker, Ace of Hearts, Ace of Trumps, High Red, Low Black.
• Martin 101 is a worldwide model, singer and artist.
• 101 is the HTTP status code indicating that a client should switch protocols (e.g. to HTTPS)
• DBAG 101s are a class of German electric locomotives.
• Radio stations such as WCBS-FM (101.1), New York, and New Jersey 101.5
• The Statue of Liberty stands 101 feet tall from base to torch
• The One Hundred First United States Congress met from January 3, 1989 to January 3, 1991 during the first two years of the President George H. W. Bush administration
• 101 Ranch Oil Company
• Taipei 101 in Taipei, Taiwan, is the world's tallest skyscraper at 101 floors
• Marina 101 in Dubai, United Arab Emirates is a 412 m (1,352 feet) tall supertall skyscraper with 101 floors under construction.
• A proposed skyscraper is planned for 101 Clarendon Street in Boston
• The Crusader 101 was an electrically-operated toy car introduced in 1964 by the Deluxe Reading Corporation of Elizabethtown, New Jersey, produced through 1966

In books

• According to Books in Print, more books are now published with a title that begins with '101' than '100'. They usually describe or discuss a list of items, such as 101 Ways to... or 101 Questions and Answers About... . This marketing tool is used to imply that the customer is given a little extra information beyond books that include only 100 items. Some books have taken this marketing scheme even further with titles that begin with '102', '103', or '1001'. The number is used in this context as a slang term when referring to "a 101 document" what is usually referred to as a statistical survey or overview of some topic.
• Room 101 in George Orwell's novel Nineteen Eighty-Four.
• The 101 Ranch written by Ellsworth Collings in collaboration with Alma Miller England, narrates the history of the Miller Brothers 101 Ranch
• The Professors: The 101 Most Dangerous Academics in America is a 2006 book by David Horowitz
• The Secret Agent on Flight 101 is Volume 46 in the original The Hardy Boys book series
• The Hundred and One Dalmatians, or "The Great Dog Robbery" is a 1956 children's novel by Dodie Smith

In film

• "Neo's number" in the 1999 sci-fi action movie The Matrix, according to one of the producers in The Matrix Revisited. It is the number on numerous significant doors in the movie; for example it is Neo's flat number at the beginning of the movie.
• Arnold Schwarzenegger's terminator model in The Terminator and in Terminator 2 was a T-800 Model 101.
• Channel 101 is a short film festival in Los Angeles with formats of a pilot under five minutes in length
• One Hundred and One Dalmatians by Dodie Smith (and the various movie versions thereof).
• 101 Reykjavík is a 2000 film set in Reykjavík, Iceland based on a book of the same name by Hallgrímur Helgason
• Life 101 is a 1995 film, starring Corey Haim and Ami Dolenz
• Occupation 101 a documentary film about the life of Palestinians under the Israeli occupation.

In music

• "Back to the 101" is a song by Albert Hammond, Jr.
• "Murder 101" is a song by The Wallflowers
• 101 is a live album and documentary by Depeche Mode released in 1989
• 101 Strings was a term for an easy listening symphonic music organization
• Highway 101 is an American country music band
• The 101'ers were a London rock band from the 1970s, notable as being the band that Joe Strummer left to join The Clash
• Punk Rock 101 is a song by Bowling For Soup

In television

• Room 101, a BBC comedy television series, named after Orwell.
• The 101, an in-house channel on DirecTV's satellite service
• Zoey 101 is an American live-action situation comedy television series that is a TEENick show on Nickelodeon, which debuted in 2005, starring Jamie Lynn Spears
• 101 Was also a Robot built for the UK TV series Robot Wars, supposedly costing only £1.01 to build
• The Six Million Dollar Man aired for 101 episodes on ABC from 1974 to 1978
• 101 Dalmatians: The Series. It is a spin off from the 1961 movie of the same name

In sports

• The 2005 World Series between the Chicago White Sox and Houston Astros was the 101st Fall Classic
• Buster Martin trained twice a week at his boxing club in Britain at age 101
• The highest number used to win a Formula 1 Grand Prix (Alberto Ascari 1953 German GP)

See also

• List of highways numbered 101

References

• Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): page 133