Probable prime
number that satisfies a given necessary condition for primality
In mathematics, particularly number theory, a probable prime is a whole number that is likely to be prime by having passed a probabilistic test such as Fermat's primality test. Probable primes may be composite, but the tests are designed so they are really unlikely to be composite. These probabilistic tests are easier to do than tests that actually guarantee primality, and the composite probable primes are useful too in encryption that uses prime numbers.
