If a prime number is a two digit number and the difference between its one digit number and its ten digit number is 7, then the prime number is zero______ .

If a prime number is a two digit number and the difference between its one digit number and its ten digit number is 7, then the prime number is zero______ .

There are 70, 81 and 92 double-digit numbers with ten digits larger than seven, and 18 and 29 double-digit numbers with ten digits larger than seven, among which only 29 is prime