Answer:
i think its 19
Explanation:
Consider the provided number.
Prime number: A prime number is a whole number which is greater than 1 and the factors of the number are 1 and itself.
The prime factorization of the provided numbers are:
19 = 1×19
28 = 2×2×7
49 = 7×7
63 =7×9
So the answer is 19