Forty-one is the 13th smallest prime number. The next is forty-three, with which it comprises a twin prime. Forty-one is also a Sophie Germain prime and a Newman-Shanks-Williams prime. 41 is the smallest Sophie Germain prime to start a Cunningham chain of the first kind of three terms, {41, 83, 167}. It is an Eisenstein prime with no imaginary part and real part of the form 3n − 1.
The number figures in the polynomial f(n) = n2 + n + 41, which yields primes for 0 ≤ n centered square number.

In science
The atomic number of niobium.

Astronomy
Messier object M41, a magnitude 5.0 open cluster in the constellation Canis Major
The New General Catalogue object NGC 41, a spiral galaxy in the constellation Pegasus
The Saros number of the solar eclipse series which began on -1588 May 28 and ended on -308 July 5. The duration of Saros series 41 was 1280.1 years, and it contained 72 solar eclipses.
The Saros number of the lunar eclipse series which began on -1268 March 18 and ended on 30 May 6. The duration of Saros series 41 was 1298.1 years, and it contained 73 lunar eclipses.
In music
The number 41 is "encoded" in much of the music of Johann Sebastian Bach. Bach may have considered this number a sort of signature, since given A = 1, B = 2, C = 3, etc., then B + A + C + H = 14 and J + S + B + A + C + H = 41.
the number of the last symphony of Wolfgang Amadeus Mozart (note: '37' is not in the canon)
#41 is a song by Dave Matthews Band
The band Sum 41

In sports
The retired number of the back of the uniform worn by Hall of Famers Tom Seaver of the New York Mets and by Eddie Mathews of the Atlanta Braves.
Worn by Dallas Mavericks Power Forward Dirk Nowitzki
The 41st Super Bowl, Super Bowl XLI.
Reed Sorenson's Nascar Nextel Cup number.

In other fields
Forty-one is also:
the model number of the HP-41C/CV/CX
a number frequently referred to in Arthur C. Clarke's series of books known as the Rama Cycle. Michael O'Toole's password for the Trinity operation is heavily encoded with the number 41. Also the virus that exists on New Eden is known as RV-41.
the international direct dialing (IDD) code for Switzerland.
Charlton Heston's designation as a galley slave in the film Ben-Hur.
C-41 process is the film developing process for 35mm color negative film.
The code number given to Tetsuo Shima by scientists in the manga and 1988 film Akira
The number that appears on Trini Alvarado's forehead in Peter Jackson's The Frighteners
Jonathan Pryce's destination level for his apartment in Terry Gilliam's Brazil
Billy Cole's jersey number in the Tony Scott film The Last Boy Scout
George W. Bush's nickname for his father, George H. W. Bush, the 41st President of the United States.
Montana is the 41st state of the United States.
41 shots were fired into Amadou Dialou, an African immigrant in New York City, causing a controversy over racial profiling.
In The Matrix, Morpheus is aggressively questioned in the 41st floor of the government building, in reference to the murder of Diallo.
Renuka's number: 41 used in Sametime Connect for first time in the field of Telecom.
In numerology, U=21,S=19,A=1.

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