Question

Sum of the odd proper divisors of N = $5^2\ast 3^1\ast 7^1\ast {17}^1\ast 2^3$.

Answer 1

Now, the sum of odd proper divisors is
$(5^0+5^1+5^2)(3^0+3^1)\left(\right(7^0+7^1\left)\right({17}^0+{17}^1)-1$
$=31\times 4\times 8\times 18-1=17856-1=17855$
(Here, 2 as a factor and 1 as a divisor are to be excluded.)