{ "id": "2007.03088", "version": "v1", "published": "2020-07-06T21:55:01.000Z", "updated": "2020-07-06T21:55:01.000Z", "title": "Arithmetic properties of the sum of divisors", "authors": [ "Tewodros Amdeberhan", "Victor H. Moll", "Vaishavi Sharma", "Diego Villamizar" ], "categories": [ "math.NT" ], "abstract": "The divisor function $\\sigma(n)$ denotes the sum of the divisors of the positive integer $n$. For a prime $p$ and $m \\in \\mathbb{N}$, the $p$-adic valuation of $m$ is the highest power of $p$ which divides $m$. Formulas for $\\nu_{p}(\\sigma(n))$ are established. For $p=2$, these involve only the odd primes dividing $n$. These expressions are used to establish the bound $\\nu_{2}(\\sigma(n)) \\leq \\lceil\\log_{2}(n) \\rceil$, with equality if and only if $n$ is the product of distinct Mersenne primes, and for an odd prime $p$, the bound is $\\nu_{p}(\\sigma(n)) \\leq \\lceil \\log_{p}(n) \\rceil$, with equality related to solutions of the Ljunggren-Nagell diophantine equation.", "revisions": [ { "version": "v1", "updated": "2020-07-06T21:55:01.000Z" } ], "analyses": { "subjects": [ "11A25", "11D61", "11A41" ], "keywords": [ "arithmetic properties", "odd prime", "ljunggren-nagell diophantine equation", "distinct mersenne primes", "divisor function" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }