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# Python2.x Python Exercise Instance 19 [ Python 100 Examples](#) **Question:** A number is called a "perfect number" if it is exactly equal to the sum of its factors. For example, 6=1＋2＋3. Write a program to find all perfect numbers within 1000. **Program Analysis:** Please refer to the program (#). Program source code: ## Instance #!/usr/bin/python# -*- coding: UTF-8 -*-from sys import stdout for j in range(2,1001): k = []n = -1 s = j for i in range(1,j): if j % i == 0: n += 1 s -= i k.append(i)if s == 0: print(j)for i in range(n): stdout.write(str(k))stdout.write('')print(k) The output of the above instance is: 61 2 3281 2 4 7