lqdoj.edu.vn/problem/for05 PYTHON

import math
n=int(input())
a=int(math.sqrt(n))
b=0
for i in range(1,a+1):
    if n%i==0:
        b += i + int(n/i)
if a*a ==n:
    b -= a
if b == 2*n:
    print("YES")
else:
    print("NO")

from math import sqrt

n = int(input())
sum_of_divisors = 1
for i in range(2, int(sqrt(n)) + 1):
    if n % i == 0:
        sum_of_divisors += i
        if i != n // i:
            sum_of_divisors += n // i
if sum_of_divisors == n and n != 1:
    print("YES")
else:
    print("NO")