English

On the Lehmer's problem involving Euler's totient function

Number Theory 2019-07-02 v2

Abstract

The Euler's totient function φ(n) \varphi(n) counts the positive integers up to a given integer n n that are relatively prime to n n . We solve a problem due to Lehmer that there is no composite number n n such that φ(n)n1 \varphi(n)\mid n-1 . We also note that there are infinitely many primes that are not Sophie Germain primes.

Keywords

Cite

@article{arxiv.1711.08313,
  title  = {On the Lehmer's problem involving Euler's totient function},
  author = {Huan Xiao},
  journal= {arXiv preprint arXiv:1711.08313},
  year   = {2019}
}

Comments

There is an error in the proof of Theorem 2.3

R2 v1 2026-06-22T22:54:05.697Z