Matchable numbers
Number Theory
2026-05-26 v2 Combinatorics
Abstract
We say a natural number is matchable if there is a bijection from the set of divisors of to the set , where corresponding numbers are relatively prime. We show that the set of matchable numbers has an asymptotic density, which we compute, and we show that every squarefree number is matchable. We also present some related unsolved problems.
Cite
@article{arxiv.2604.05304,
title = {Matchable numbers},
author = {Nathan McNew and Carl Pomerance},
journal= {arXiv preprint arXiv:2604.05304},
year = {2026}
}
Comments
Code to generate tables is included as an ancillary file