19
19
19 is the prime number.
19
19 is prime.
19 is the prime number.
9 is the prime number.
19 is the only one that only has 1 and itself as factors. It is the prime number.
19 is a prime.
19 is a prime number, so it has no prime factorization.
19 is a prime number.19 is a prime number.19 is a prime number.19 is a prime number.
Any number whose digits total 3, 6 or 9 is divisible by 3 and, therefore, not prime.