My definition of pure monotheism is that no single entity comes close to being revered as much as the single god. Yes it can appreciate prophets, but the prophets should not be praised as much or more than the god. Also, it should not be required to obey anyone except the god. But it is permissible to obey the leaders as long as the instructions they give come directly from the single god.
Islam (the religion I am originally from) does not fit this definition, as they praise Muhammad too much, they are required to obey his independent commands, they are encouraged to ask for forgiveness through him, and they believe that the god even prays for Muhammad. To me, this is raising a human way too close to the status of the god. Does Judaism do this with its prophets?