  Let $\chi$ be an irreducible character of a group $G,$ and
$S_c(G)=\sum_{\chi\in {\rm Irr}(G)}{\rm cod}(\chi)$ be the sum of the codegrees
of the irreducible characters of $G.$ Write ${\rm fcod}
(G)=\frac{S_c(G)}{|G|}.$ We aim to explore the structure of finite groups in
terms of ${\rm fcod} (G).$ On the other hand, we determine the lower bound of
$S_c(G)$ for nonsolvable groups and prove that if $G$ is nonsolvable, then
$S_c(G)\geq S_c(A_5)=68,$ with equality if and only if $G\cong A_5.$
Additionally, we show that there is a solvable group so that it has the
codegree sum as $A_5.$
