Find such a prime number, when it adds 10 and 14, it is still prime

Find such a prime number, when it adds 10 and 14, it is still prime

Because 2 + 10 = 12, 2 + 14 = 16, prime 2 is not suitable; because 3 + 10 = 13, 3 + 14 = 17, prime 3 is suitable; because 5 + 10 = 15, 5 + 14 = 19, prime 5 is not suitable; because 7 + 10 = 17, 7 + 14 = 21, prime 7 is not suitable; because 11 + 10 = 21, 11 + 14 = 25, prime 11 is not suitable This paper classifies positive integers into module 3 congruences, that is, 3K-1, 3K + 1 (k is a positive integer). Because (3K-1) + 10 = 3K + 9 = 3 (K + 3) is a composite number, and (3K + 1) + 14 = 3K + 15 = 3 (k + 5) is a composite number, prime numbers in 3K-1 and 3K + 1 plus 10 and 14 cannot be prime numbers. Therefore, prime numbers in 3K-1 and 3K + 1 plus 10 and 14 cannot be prime numbers Integer, only when k = 1, 3K is prime, the rest are composite. So the prime number is only 3. So the answer is: 3