English

On a conjecture of Deaconescu

Number Theory 2022-06-22 v1

Abstract

In 2000 Deaconescu raised a question whether there exists a composite nn for which S2(n)ϕ(n)1S_2(n)|\phi(n)-1, where ϕ(n)\phi(n) is Euler's function and S2(n)S_2(n) is Schemmel's totient function. In this paper we prove that any such nn is odd, squarefree and has at least seven distinct prime factors. We also prove that any such nn with exactly KK distinct prime divisors is necessarily less than 22K+12^{2^{K+1}}.

Keywords

Cite

@article{arxiv.2206.10355,
  title  = {On a conjecture of Deaconescu},
  author = {Elchin Hasanalizade},
  journal= {arXiv preprint arXiv:2206.10355},
  year   = {2022}
}

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4 pages