If you realy think a 16 MP sensor has 64 million subpixels, you're wrong.
(except for some special snowflakes like Super-CCD and Foveon-X3)
The sensors with a Bayer matrix filter don't operate that way, they have colored pixels and no subpixels.
They extrapolate the missing color informations from neighbouring pixels.
You could use a demosaic firmware to stop doing that, but that would effectively turn your 16 MP sensor into a 4 MP sensor and good luck selling that to custumers.