Comment by surfingdino

You are right about the differences in the number of sensors, there may be more. I prefer to talk about photosites, because additional properties like photosite size or sensor photosite density help me make better decisions when I'm selecting cameras/sensors for a photo project. For example, a 24MP M43 sensor is not the same as a 24MP APS-C or FF sensor, even though the image files they produce have the same number of pixels. Similarly, a 36MP FF sensor is essentially the same a 24MP APS-C sensor, it produces image files that contain more pixels from a wider field of view, but the resolution of the sensor stays the same, because both sensors have the same photosite density (if you pair the same lens with both sensors).