Visible light is anything between 1.65eV and 3.10eV, so the answer is somewhere between these values. Naively we could average this to 2.375 eV, but that would not be actual average of full spectrum white light.
As I understanding it, what we perceive as white light, in daylight conditions, is the visible spectrum of roughly 5500K black body radiation (which has more energy on the blue side). I'm not sure how we'd get the average eV of the photons that make it up.
If you have another standard measure of "white" sunlight, I could be happy with that too.
edit: I am not a student. I am not studying physics or mathematics. Sorry I cannot give working beyond attempting to average the highest and lowest eV and saying "obviously that's wrong" (which I did in the question already). If you think the answer to this question can be googled then please provide your google query and a link to something that isn't a physics course.