41 (number)

In mathematics

• the 13th smallest prime number. The next is 43, making both twin primes.
• the sum of the first six prime numbers.
• a regular prime.
• a Ramanujan prime.
• a harmonic prime.
• a good prime.
• the 12th supersingular prime.
• a Newman–Shanks–Williams prime.
• the smallest Sophie Germain prime to start a Cunningham chain of the first kind of three terms,.
• an Eisenstein prime, with no imaginary part and real part of the form 3n − 1.
• a Proth prime as it is 5 × 2³ + 1.
• the largest lucky number of Euler: the polynomial yields primes for all the integers k with.
• the sum of two consecutive squares, which makes it a centered square number.
• the sum of the first three Mersenne primes, 3, 7, 31.
• the sum of the sum of the divisors of the first 7 positive integers.
• the smallest integer whose reciprocal has a 5-digit repetend. That is a consequence of the fact that 41 is a factor of 99999.
• the smallest integer whose square root has a simple continued fraction with period 3.
• a prime index prime, as 13 is prime.

  In other fields

• In Mexico "cuarenta y uno" is slang referring to a homosexual. This is due to the 1901 arrest of 41 homosexuals at a hotel in Mexico City during the government of Porfirio Díaz. See: Dance of the Forty-One.
• An international calling code for Switzerland.