400 (number) third perfect number, a number whose divisors add up to the actual number (1+2+4+8+16+31+62+124+248=496). 497 = 7 × 71, sum of five consecutive primes (89 + 97 + 101 + 103 + 107) 498 = 2 × 3 × 83, sphenic number, untouchable number, admirable number, abundant number A prime number, Chen prime 400 (number) 400 (four hundred) is the natural number following 399 and preceding 401. 400 is the square of 20. 400 is the sum of the powers of 7 from 0 to 3, thus making it a repdigit in base 7 (1111). A circle is divided into
Square root of 2 method of computing square roots, which is one of many methods of computing square roots. It goes as follows: First, pick a guess, ; the value of the guess affects only how many iterations are required to reach an approximation of a certain accuracy. Then, using that guess, iterate through the following recursive computation: The more iterations through the algorithm (that is, the more computations performed and the greater ""), the better approximation of the square root of 2 is achieved. Each iteration approximately doubles the number of correct digits. Starting with the next approximations are The value of was