195761

Is there a quick way to tell if the total is going to be even or odd?
Yes, you can take the top-right number and the bottom-left number, bottom-right number twice on the grid and add them up, if they are odd when added the final number will be odd, if they add up to even then the final number will even.
For example :
1+6+6+2=15 15 is odd so the final number will be odd and it is, 125.