10500...00001 (121-digits)

This number is a prime.

                    1 0500000001 7350000000 1385000000 0198500000 0017950000
0001106000 0000113600 0000013460 0000001946 0000000176 6000000019 7600000001

The smallest prime formed from the concatenation of n consecutive n-digit primes with reversed digits, i.e., {10500000001, 73500000001, 38500000001, 98500000001, 79500000001, 10600000001, 13600000001, 34600000001, 94600000001, 76600000001, 97600000001}, (case n=11). [Bajpai]