32222...22223 (110-digits)

This number is a prime.

                                 3222222222 2222222222 2222222222 2222222222
2222222222 2222222222 2222222222 2222222222 2222222222 2222322222 2222222223

This prime-digit prime has sum of digits equal to 223, and 223 has sum of digits equal to 7. It is the largest prime-digit prime with this property if all primes in the sequence are restricted to prime-digit primes, where the final iterated sum of digits is 7. The prime-digit prime for the next term of this sequence will be outrageously gigantic. [Sumpeloh]