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almost perfect number

natural number whose proper divisors sum to one less than itself
Class type of: integer Q1526045

Facts

5 properties
Subclass of
integer[1]
Defining formula
\sigma(n)=2n-1
Different from
quasiperfect number[2]
In defining formula
\sigma, n
Maintained by WikiProject
WikiProject Mathematics[3]
🏷️ Also known as
en almost perfect number de fast perfekte Zahl es número casi perfecto fi Lähes täydellinen luku fr nombre presque parfait he מספר כמעט משוכלל hu majdnem tökéletes számok id Bilangan hampir sempurna it Numero lievemente difettivo ja 概完全数 nl bijna perfect getal ro număr aproape perfect ru Слегка недостаточное число ru Слегка недостаточные числа sv Nästan-perfekt tal uk Злегка недостатнє число uk Злегка недостатні числа vi Số gần hoàn thiện thiếu zh 殆完全數 zh-hans 殆完全数
🔖 Identifiers · 3
Freebase ID
/m/01vmvm
MathWorld ID
AlmostPerfectNumber
Microsoft Academic ID (discontinued)
2781267937

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🔗 Connections
Maintained by WikiProject 1
WikiProject Mathematics
Subclass of 1
integer
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References

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Direct Wikidata claims

  1. [1] ↑ . wikidata.org.
  2. [2] ↑ . wikidata.org.
  3. [3] ↑ . wikidata.org.

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Edit History

Rolling log of changes to this entity's Wikidata record. Values shown reflect the current state of each edited property — follow the history link to see the precise diff for any edit.

  1. 6w ago · YoshiRulz · 2026-09-29 view diff on Wikidata ↗
    Different from → quasiperfect number
    Maintained by WikiProject → WikiProject Mathematics
    Subclass of → integer
    "Created claim: Different from: quasiperfect number"
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