Phrase guide

perfect number

noun · 1 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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1

noun

Meaning 1

A number that is the sum of all of its divisors except itself.

Definition source: English Wiktionary via Wiktextract

Topics: mathematics, number-theory, sciences

Examples

  • The factors of 6 are 1, 2, 3 and 6, and 1 + 2 + 3 = 6, so 6 is a perfect number.
  • 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.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

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

Across languages

Translations

25 source translations are retained for this English entry.

  • Catalan: nombre perfecte — a number that is the sum of all of its divisors except itself
  • Chinese Mandarin: 完全數 /完全数 (wánquánshù) — a number that is the sum of all of its divisors except itself
  • Dutch: perfect getal — a number that is the sum of all of its divisors except itself
  • Finnish: täydellinen luku — a number that is the sum of all of its divisors except itself
  • French: nombre parfait — a number that is the sum of all of its divisors except itself
  • Galician: número perfecto — a number that is the sum of all of its divisors except itself
  • German: vollkommene Zahl — a number that is the sum of all of its divisors except itself
  • German: perfekte Zahl — a number that is the sum of all of its divisors except itself
  • German: ideale Zahl — a number that is the sum of all of its divisors except itself
  • Icelandic: fullkomin tala — a number that is the sum of all of its divisors except itself
  • Old Irish: áram foirbthe — a number that is the sum of all of its divisors except itself
  • Italian: numero perfetto — a number that is the sum of all of its divisors except itself
  • Japanese: 完全数 (kanzen-su) — a number that is the sum of all of its divisors except itself
  • Korean: 완전수 (wanjeonsu) — a number that is the sum of all of its divisors except itself
  • Latin: numerus perfectus — a number that is the sum of all of its divisors except itself
  • Norwegian Bokmål: perfekt tall — a number that is the sum of all of its divisors except itself
  • Polish: liczba doskonała — a number that is the sum of all of its divisors except itself
  • Portuguese: número perfeito — a number that is the sum of all of its divisors except itself
  • Romanian: număr perfect — a number that is the sum of all of its divisors except itself
  • Russian: соверше́нное число́ (soveršénnoje čisló) — a number that is the sum of all of its divisors except itself
  • Slovak: dokonalé číslo — a number that is the sum of all of its divisors except itself
  • Spanish: número perfecto — a number that is the sum of all of its divisors except itself
  • Swedish: perfekt tal — a number that is the sum of all of its divisors except itself
  • Tagalog: himpit na bilang — a number that is the sum of all of its divisors except itself
  • Turkish: mükemmel sayı — a number that is the sum of all of its divisors except itself