Given a number n, check it is the Almost Perfect number or not. Almost perfect number is a natural number whose sum of all divisors including 1 and the number itself is equal to 2n – 1.
Input: n = 16 Output: Yes Explanation: sum of divisors = 1 + 2 + 4 + 8 + 16 = 31 = 2n - 1 Input: n = 9 Output: No Explanation: sum of divisors = 1 + 3 + 9 ≠ 2n - 1
The almost perfect numbers are found to be of the form 2^k(k = 0, 1, 2, 3, 4, ..). However it is not proved.
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