English

Generalizing the Lehmer's totient problem

Group Theory 2021-10-27 v1

Abstract

An important unsolved question in number theory is the Lehmer's totient problem that asks whether there exists any composite number nn such that φ(n)n1\varphi(n)\mid n-1, where φ\varphi is the Euler's totient function. It is known that if any such nn exists, it must be odd, square-free, greater that 103010^{30}, and divisible by at least 1515 distinct primes. Such a number must be also a Carmichael number. In this short note, we discuss a group-theoretical analogous problem involving the function that counts the number of automorphisms of a finite group. Another way to generalize the Lehmer's totient problem is also proposed.

Keywords

Cite

@article{arxiv.2110.13318,
  title  = {Generalizing the Lehmer's totient problem},
  author = {Marius Tărnăuceanu},
  journal= {arXiv preprint arXiv:2110.13318},
  year   = {2021}
}
R2 v1 2026-06-24T07:10:55.719Z