4926644540 > 2^32, so you probably need to treat it as an "unsigned <B>long long</B>". Note that the 631677244 you're seeing is 4926644540 % 2^32.

There is an example of a programme that differentiates between long and short push-button pushes on the Arduino.cc website, but I was not taken it. However their was an example I did like the look of, ...