Is a man’s command to Satan and his addressing him, in order to ward off his whispers, considered an invocation of the absent living, which necessitates polytheism, or does the presence of Satan not render the one who commands or addresses him an infidel?

Addressing Satan when one does not see him does not constitute disbelief if the intention is to conjure his image in one's heart, similar to a worshipper saying, "Peace be upon you, O Prophet," while not seeing the Prophet (peace and blessings be upon him). This type of address is not polytheism (shirk) because it does not involve dedicating worship to other than Allah. It seems that the questioner is suffering from whispers (waswas), and he should avoid giving in to them.