practical numberA number n such that every positive integer less than n is either a divisor or a sum of distinct divisors of n. The first few practical numbers are 1, 2, 4, 6, 8, 12, 16, 18, 20, 24, ... All perfect numbers are practical. Related category TYPES OF NUMBERSAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |