There are several well-known criteria for a polynomial with integer coefficients to be irreducible over $\mathbb{Z}$, for examplee.g., Eisenstein's criterionEisenstein's criterion. I'm looking for the opposite: other than factorization, is there some sufficient condition to show that a given polynomial must be reducible (apart from demonstrating a factorization)? Ideally, I'd like some property that depends only on the coefficients appearing in the polynomial, like in Eisenstein's criterion.