Well, this is a very positive drawing.
It seems familiar to one of those illustrations from the mathematic books, so that's definitely a plus.
So anyway, the color scheme on the background is very good, too. Besides the shades of blue that you used, it's also good that you deviated from that to use other colors as well.
The pose for the character on the center, though simple, is actually very good to drive a positive message in this pic.
Good use of highlights and midtones, it's definitely one of those good forms of artwork that seems delve into one's subconscious in a good manner.