23571...66643 (2434-digits)

This number is a probable-prime (likely to be a prime but we have not (re-)proven it on this site).

The smallest titanic prime P formed from the concatenation of the first n palindromic primes, i.e., {2, 3, 5, 7, 11, 101, ..., 3460643, 3466643}, (case n=387). Curiously, P ends with the smallest palindromic beastly Sophie Germain prime (3466643). [Bajpai]