41 is: • the 13th smallest
prime number. The next is
43, making both
twin primes. • the sum of the first six prime numbers (2 + 3 + 5 + 7 + 11 + 13). • 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, {41, 83, 167}. • an
Eisenstein prime, with no imaginary part and real part of the form 3
n − 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 (42 + 52), 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==