2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/71054We study the distribution of palindromic numbers (with respect to a fixed base $g\ge 2$) over certain congruence classes, and we derive a nontrivial upper bound for the number of prime palindromes $n\le x$ as $x\to\infty$. Our results show that almost all palindromes in a given base are composite.19 pagesNumber Theory11A63; 11L07; 11N69text