We present an in-depth multiscale analysis of the conformations and dynamics of polar active polymers, comparing very dilute and very dense conditions. We unveil characteristic length and time scales, common to both dilute and dense systems, that recapitulate the conformational and dynamical properties of these active polymers upon varying both the polymer size and the strength of the activity. Specifically, we find that a correlation (or looping) length characterizes the polymer conformations and the monomer dynamics. Instead, the dynamics of the center of mass can be fully characterized by the end-to-end mean-square distance and by the associated relaxation time. As such, we show that the dynamics of individual chains in melts of polar active polymers is not controlled by entanglements, but only by the strength of the self-propulsion.
