Question

Prove that 571 is a prime number

Answer 1

Now 571 lies between the perfect squares of   (23)2 and  (24)2
 Prime numbers less than 24 are 2,3,5,7,11,13,17,19,23
Since   571 is not divisible by any of the above numbers 
            571 is a prime number

Answer 2

571 is a prime number because it has only two distinct divisors