How many hours a day on Mathematics as a successful student?
I am afraid that your computation is not even wrong.  You might as well ask how many hours a day you need to practice dribbling in order to be a professional basketball player.  

Mere knowledge of mathematics is just one component of being a professor, even a professor of pure mathematics.  To become a successful mathematics professor (or any type of professor, really), you need a lot more than just to have studied many textbooks: you need scientific creativity, you need vision, you need to be able to communicate and write well, you need to be able to teach, you need self-discipline, you need some broader understanding of how mathematics fits into the larger world, and you need many more things besides.

Moreover, one of those many things that you need is skill at extracting knowledge from texts.  The deeper your understanding becomes, the more that you will be able to see the structure of the content that you are reading, to analyze which parts are critical and which are accessory, and the less that the computation you present makes sense.

In short: yes, it takes a lot of effort on mathematics to become a professor, but the process and challenges are very different than you think.