Deficient numbers

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The deficient numbers are positive integers

n

whose sum of divisors

σ (n)

is less than

2n

(or whose sum of proper divisors

s (n) : σ (n) − n

is less than

n

).

The deficient numbers are listed in A005100. See A125499 for the even deficient numbers and A247328 for the odd deficient numbers.

See also

• Perfect numbers
• Abundant numbers