The proper divisors of 12 are 1, 2, 3, 4 and 6. A proper divisor of an integer N is a positive divisor of N that is less than N. What is the sum of the proper divisors of the sum of the proper divisors of 280?
+2886
The proper divisors of 12 are 1, 2, 3, 4 and 6.
A proper divisor of an integer N is a positive divisor of N that is less than N.
What is the sum of the proper divisors of the sum of the proper divisors of 280?
The proper divisors of 280 are 1, 2, 4, 5, 7,
8, 14, 20, 28, 35,
40, 56, 70, & 140 Sum = 440
The proper divisors of 440 are 1, 2, 4, 5, 8,
10, 11, 20, 22, 40,
44, 55, 88, 110, & 220 Sum = 640
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