A twice prime number is defined as a prime number whose digits are also prime. For example: $23$ is prime. It is made up of the digit $2$, which is prime, and the digit $3$, which is also prime. Therefore, $23$ is twice prime. Counter example: $19$ is prime, but $1$ nor $9$ is prime and therefore $19$ is not twice prime.
Does twice prime only consist of two prime digits? Or can we have a three digit prime which can qualify as twice prime?