func sumNumberProperDivisors(_ num: Int) -> Int {
var sum = 0
for i in 1...(num / 2) {
if num % i == 0 {
print("\(i), ", terminator: "")
sum += i
}
}
return sum
}
let sum = sumNumberProperDivisors(220)
print("\n\(sum)")
/*
run:
1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110,
284
*/