This app can be used to check whether the given number is a probable prime number or not . The error probability is estimated to be less than 7.3*10^(-7) .Time complexity of the algorithm is O(3*log^2(n)*log(log(n))*log(log(log(n)))) .It checks primality of 1000 digit number in seconds. You can use arithmetic operators +,-,*,/,^ and parentheses to enter a number of a special form. There is no upper limit to the number you can enter.
For more info visit: https://math.stackexchange.com/q/3436623 .