deficient number
natural integer number for which the sum of its proper strict divisors (other than itself) is less than the number itself
en-US/dɪˈfɪʃənt ˈnʌmbɚ/
en-GB/dɪˈfɪʃnt ˈnʌmbə/
natural integer number for which the sum of its proper strict divisors (other than itself) is less than the number itself