2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/127595In this article we prove that equation $ϕ(x)=n$, for a fixed $n$, admits a finite number of solutions, we find the general form of these solutions, and we show that: if $x_0$ is a unique solution of this equation then $x_0$ is a product of a very large number of primes (we conjecture that the number of such primes is infinite).4 pagesGeneral Mathematics11K65text