41

41 is a natural number that comes after 40 and before 42. It is an odd prime and the thirteenth prime number. It is also the sum of the first six primes: 2 + 3 + 5 + 7 + 11 + 13 = 41.

In number theory, 41 is a twin prime with 43 and a Sophie Germain prime since 2×41 + 1 = 83 is prime. It also appears as the hypotenuse in the primitive Pythagorean triple (9, 40, 41).

In numeral systems, 41 in binary is 101001 and in hexadecimal is 29. In Roman numerals it is XLI. In ASCII, decimal 41 corresponds to the right parenthesis character ).

In science and astronomy, 41 denotes the chemical element niobium (Nb) and Messier 41, an open star cluster in Canis Major. In culture, 41 is the designation of George H. W. Bush, the 41st U.S. president, and is the title of a memoir by his son, 41: A Portrait of My Father.