Talk:Numbers whose count of divisors is prime: Difference between revisions
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That means all n has to be m*m.<BR> |
That means all n has to be m*m.<BR> |
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Therefor only square numbers need to be tested. |
Therefor only square numbers need to be tested. |
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:Brilliant, thanks! --[[User:PureFox|PureFox]] ([[User talk:PureFox|talk]]) 15:42, 11 July 2021 (UTC) |
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Revision as of 15:42, 11 July 2021
The question is: Which numbers got odd count of divisors
If you look at prime decompostion of a number like n = p1^a*p2^b*...pn^z,
than the count of divisors is CoD = (a+1)*(b+1)*(c+1)*....(z+1).
That is only possible if all a..z are even.
That means all n has to be m*m.
Therefor only square numbers need to be tested.