If so, then the brochure fails to distinguish between a pixel and a subpixel.
1,366 x 768 = 1,049,088. Rounded off, that's 1 million pixels. 1 million pixels x 3 for each R, G and B = 3 million subpixels, not 3 million pixels.
A megapixel is 1 million pixels, not 1 million subpixels.