Retrieving the hex code of the color of a given pixel

I have used resize_to_fill down to a [1,1] size thus reducing the image to a single pixel containing what is basically the average color of the entire image (provided the image does not have a huge disparity between height and width, of course). Now I'm attempting to retrieve the color of this single pixel in hex format. From the terminal window I am able to run the convert command like this: conv