List questions from divisor-sum | MathQA

Is $650$ the only solution not fitting in the family?

Published on 15 Nov 2022 - 9:18

Can this inequality involving the deficiency and sum of aliquot divisors be improved? - Part II

Published on 28 Mar 2026 - 0:30

Find all positive integers $n$ such that $\sigma(n) = n + 1 + \sigma(n+1)$

Published on 05 Dec 2022 - 16:05

On a consequence of $G \mid I \iff \gcd(G, I) = G$ (Re: Odd Perfect Numbers and GCDs)

Published on 28 Mar 2026 - 0:31

On the prime factorization of $n$ and the quantity $J = \frac{n}{\gcd(n,\sigma(q^k)/2)}$, where $q^k n^2$ is an odd perfect number

Published on 28 Mar 2026 - 0:30

The mean square of $d_k(n)$

Published on 26 Mar 2026 - 12:58

If $p^k m^2$ is an odd perfect number with special prime $p$ and $p = k$, then $\sigma(p^k)/2$ is not squarefree.

Published on 28 Mar 2026 - 0:30

If $p$ is a prime number and $k$ is a positive integer, is it true that $\sigma_1(p^k) > 1 + k (\sqrt{p})^{1+k}$?

Published on 15 Jan 2023 - 10:26

Define $\partial(n\mid x) = \partial(q_0 \cdots q_i \mid x) = \sum_{j=0}^i (-1)^i q_j (\frac{n}{q_j} \mid x)$. What does homology measure?

Published on 16 Jan 2023 - 1:43

Euler product involving divisor function

Published on 21 Jan 2023 - 22:14

Sum of Factors Question

Published on 26 Jan 2023 - 10:59

Why is it that, if there are no odd perfect numbers, then there are no other $3$-perfect numbers, apart from the six known, as of the year $1643$?

Published on 28 Mar 2026 - 0:30