Odd abundant number
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Examples[change | change source]
- The first example is 945 (33× 5× 7). Its prime factors are 3, 5, and 7. The next following eleven odd abundant numbers are
1575, 2205, 2835, 3465, 4095, 4725, 5355, 5775, 5985, 6435, 6615.
- Odd abundant numbers below 500000 are in On-Line Encyclopedia of Integer Sequences A005231.
Formulas[change | change source]
The following formula
The second formula
The third formula
fails if .
Properties[change | change source]
- An calculation was given by Iannucci shows how to find the smallest abundant number not divisible by the first n primes.
- An abundant number with abundance 1 is called a quasiperfect number, although none have yet been found. A quasiperfect number must be an odd square number having a value above 1030.