I have recently installed QGIS 2.18.19 LTR with the OSGEO464W installer. My system is Windows 7 64bits. I installed Eclipse and PyDev successfully. However when configuring PyDev I have to indicate the 'Interpreter Executable' which in the tutorial I am following would be C:\ProgramFiles\QGIS2.18\bin\python.exe.
If I search the file, I find it in C:\OSGEO4W64\apps\Python36\python.exe, however I am certain that I am running Python 2.7.5 when I check in the python console from inside QGIS and not Python 3. My question is: where can I find the executable or the file that opens the right python 2.7.5, what is the name that I have to provide for the PyDev Interpreter.