See the map:
http://www.au.af.mil/au/awc/awcgate/gabrmetz/map3a.gif
No, it had 20 provinces.
20.
The rulership of the Persian king of the 20 provinces with Persian governors.
Satrapies.
The king and his council, and the 20 governors who controlled the provinces of the Persian Empire.
Twenty Satrapies (Provinces).
The territories of the Persian Empire were called satrapis.
Twenty provinces (Satrapies).
Satrapies (Provinces).
King Darius the Great.
Satrap
The Persian Empire was not a Mesopotamian empire - it included Mesopotamia as merely one of it's twenty provinces which stretched from Libya to today's Pakistan..