The sum of all the proper divisors of 9900 is (A) 33851 (B) 23952 (C) 23951 (D) none

Sum of all the odd divisors of 720 is

If sum_(r=1)^20(r^2+1)r!=k!20 then sum of all divisors of k of the from 7^n, n epsilin N is (A) 7 (B) 58 (C) 350 (D) none of these

If sum_(r=1)^20(r^2+1)r! =k!20 then sum of all divisors of k of the from 7^n, n epsi N is (A) 7 (B) 58 (C) 350 (D) none of these

The sum of all 2-digit number divisible by 5 is (a) 945 (b) 1035 (c) 1230 (d) 1245 (e) None of these

Sum of all divisors of 5400 whose unit digit is 0 is

The sum of all positive divisors of 242 except 1 and self is