20 is the third composite number comprising the product of a squared prime and a prime, and also the second member of the (22)q family in this form.
20 has an aliquot sum of 22 (110% in abundance). Accordingly, 20 is the third abundant number and demonstrates an 8-member aliquot sequence; {20, 22, 14, 10, 8, 7, 1, 0}.
20 is the 4th composite number in the 7-aliquot tree. Two numbers have 20 as their aliquot sum; the discrete semiprime34 and the squared prime 361. Only 2 other square primes are abundant 12 and 18.