On an inequality about Euler’s totient function

Cheng-Ting Wang
Notes on Number Theory and Discrete Mathematics
Print ISSN 1310–5132, Online ISSN 2367–8275
Volume 31, 2025, Number 2, Pages 299–304
DOI: 10.7546/nntdm.2025.31.2.299-304
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Authors and affiliations

Cheng-Ting Wang
Independent researcher
2F., No. 382, Daye Rd., Beitou Dist., Taipei City 112029, Taiwan

Abstract

In this paper, we show that when N_k is a primorial and \varphi(N_k) is Euler’s totient function, the inequality \varphi(N_k) < \frac{N_k}{e^{\gamma}\log{\log{N_k}}} holds for all positive integer k > 44.

Keywords

  • Euler’s totient function
  • Prime numbers
  • Primorials

2020 Mathematics Subject Classification

  • 11A25
  • 11A41

References

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Manuscript history

  • Received: 21 October 2024
  • Revised: 16 April 2025
  • Accepted: 13 May 2025
  • Online First: 29 May 2025

Copyright information

Ⓒ 2025 by the Author.
This is an Open Access paper distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License (CC BY 4.0).

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Cite this paper

Wang, C.-T. (2025). On an inequality about Euler’s totient function. Notes on Number Theory and Discrete Mathematics, 31(2), 299-304, DOI: 10.7546/nntdm.2025.31.2.299-304.

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