23571...37273 (276-digits)

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

    235711 1011311511 8119131335 3373383727 7577877979 1992910301 1050110601
1131111411 1242112721 1282113331 1383113931 1434114741 1545115551 1606116361
1656116661 1747117971 1818118481 1939119891 1999130103 3020330403 3070330803
3101331513 3232332423 3353334543 3484335053 3515335353 3575336263 3656337273

The smallest googol prime formed from the concatenation of first n palindromic primes (case n=65). [Gupta]