Find the sum of the divisors of 1400. I don't want to list them all; is there an easier way?
sum((1, 2, 4, 5, 7, 8, 10, 14, 20, 25, 28, 35, 40, 50, 56, 70, 100, 140, 175, 200, 280, 350, 700, 1400)=3720
