A perfect number is a number for which the sum of its proper divisors is exactly equal to the number. For example, the sum of the proper divisors of 28 would be 1 + 2 + 4 + 7 + 14 = 28, which means th...

质数也叫素数，是只能被1和它本身整除的正整数，最小的质数是2，目前发现的最大的质数是p=2^57885161-1【注1】。判断一个数是质数的最简单的方法如下：[code="Python"]def isPrime1(n): for i in range(2, n): if n % i == 0: return False return True[/code]...