 Principal Dirichlet character

The principal Dirichlet character modulo $N$ is one on integers coprime to $N$ and zero on all other integers. Its Dirichlet L-function is $L({\chi }_0,s)=\zeta (s){\prod }_{p\mid N}(1-p^{-s})$, so it has a simple pole at one. For $N>1$ it is induced from the character of modulus one and is not a primitive Dirichlet character.