Numbers never end. Thus it is impossible to find the largest Prime number.
The largest known prime number as of 2003 is
m39 = 213,466,917-1
It has 4,053,946 digits and does not fit in this box.
73 is the largest two-digit number that is prime and has prime numbers for both of its digits.
The largest prime number that has 4 digits and begins with a 1 is 1,999.
Smallest is 11 & Largest is 77.
73 is the largest 2 digit number that is both prime and has prime numbers for both of its digits.
The largest 3 digit number whose digits are all primes is 777. The largest 3 digit number with different prime digits is 753.
It is: 73 of which 7 and 3 are both prime numbers
4,053,946
999,983
17,425,170 digits
773.
As of August 2017, the largest known prime number is 2^74,207,281 − 1, a number with 22,338,618digits.I attached a link with the 100 largest known prime numbers, there you can see the number of digits.
The largest three digit prime number whose digits are all primes is 773.