Dictionary

perfect number en · NOUN

Pronunciation

• (Southern-England) audio

Etymology

Calque of Latin numerus perfectus, with this use of perfectus itself a semantic loan from Ancient Greek τέλειος (téleios).

Meanings

1. A number that is the sum of all of its divisors except itself.
   • The factors of 28 are 1, 2, 4, 7, 14 and 28, and 1 + 2 + 4 + 7 + 14 = 28, so 28 is a perfect number.
   • The factors of 6 are 1, 2, 3 and 6, and 1 + 2 + 3 = 6, so 6 is a perfect number.

Forms

Deriveds

hyperperfect number

Relateds

amicable numbers · Mersenne prime · sociable numbers · abundant number · deficient number

Translations (25)

sk dokonalé číslo (a number that is the sum of all of its divisors except itself) · pt número perfeito (a number that is the sum of all of its divisors except itself) · sv perfekt tal (a number that is the sum of all of its divisors except itself) · it numero perfetto (a number that is the sum of all of its divisors except itself) · gl número perfecto (a number that is the sum of all of its divisors except itself) · ja 完全数 (a number that is the sum of all of its divisors except itself) · nl perfect getal (a number that is the sum of all of its divisors except itself) · ko 완전수 (a number that is the sum of all of its divisors except itself) · ca nombre perfecte (a number that is the sum of all of its divisors except itself) · de perfekte Zahl (a number that is the sum of all of its divisors except itself) · ro număr perfect (a number that is the sum of all of its divisors except itself) · es número perfecto (a number that is the sum of all of its divisors except itself) · la numerus perfectus (a number that is the sum of all of its divisors except itself) · is fullkomin tala (a number that is the sum of all of its divisors except itself) · de vollkommene Zahl (a number that is the sum of all of its divisors except itself) · tr mükemmel sayı (a number that is the sum of all of its divisors except itself) · ru соверше́нное число́ (a number that is the sum of all of its divisors except itself) · sga áram foirbthe (a number that is the sum of all of its divisors except itself) · de ideale Zahl (a number that is the sum of all of its divisors except itself) · fr nombre parfait (a number that is the sum of all of its divisors except itself) · fi täydellinen luku (a number that is the sum of all of its divisors except itself) · nb perfekt tall (a number that is the sum of all of its divisors except itself) · pl liczba doskonała (a number that is the sum of all of its divisors except itself) · tl himpit na bilang (a number that is the sum of all of its divisors except itself) · cmn 完全數 /完全数 (a number that is the sum of all of its divisors except itself)