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41 (number)

41 is the natural number following 40 and preceding 42.

List of numbers — Integers << 40 41 42 43 44 45 46 47 48 49 >>
Cardinal	forty-one
Ordinal	41st(forty-first)
Factorization	prime
Roman numeral	XLI
Binary	101001
Hexadecimal	29

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.

The number figures in the polynomial f(n) = n² + n + 41, which yields primes for 0 <= n < 40.

Forty-one is the sum of two squares, 4² + 5², as well as the sum of the first six prime numbers, and also the sum of three primes (11 + 13 + 17). It is a centered square number.

Forty-one is also:

• the atomic number of niobium.
• the model number of the HP-41C/CV/CX
• in A Thousand and One Nights, the number of thieves accompanying Ali Baba.
• a number 'encoded' in a lot 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 code for direct dial international phone calls to Switzerland.
• The year A.D. 41, 41 BC, or 1941.
• #41 is a song by Dave Matthews Band.
• C-41 is the film developing process for 35mm color negative film.