Rsa, Miller Rabin, Prime Numbers, Algorithms, Cryptography.
more square roots of 1 than is allowed mod n if n were prime. How often is a random number prime? If you pick a random number between 1 and 100 you have about a 25% chance of choosing a prime. Between 1 and 1000 only about 18% of numbers are prime. For a large number x the proportion of primes