A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two or more smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number.[1]
To test for whether a number n is prime, test whether the number is divisible by all integers from 2 to the square root of n.
This method trial division is very slow and can improved by other methods such as the AKS primality test.
Review MathsIsFun: Prime Numbers Chart and Calculator. Compare your list of prime numbers less than 100 for accuracy. Use the prime number calculator to find a prime number greater than 1000.