the biggest number you can store this way is 2,147,483,647 seconds after 1 january 1970. this means 19th january 2038 at 03:14:07 utc. the problem begins one second after this time. the computer will add 1 to this 32-bit number, and the computer will set the value to "negative" 2,147,483,648 seconds. this means 13th december 1901 at 20:45:52 utc. depending on how the computer has been programmed, the computer could behave incorrectly or even stop running.