Two numbers are amicable when the sum of the divisors of one (except itself) equal the other.
20 is divisible by 1, 2, 4, 5 and 10.
32 is divisible by 1, 2, 4, 8, 16.
1 + 2 + 4 + 5 + 10 = 26, while 1 + 2 + 4 + 8 + 16 = 31
Therefore, 20 and 32 are not amicable numbers.