50000...00027 (31-digits)

This number is a prime.

                                          5 0000000000 0000000000 0000000027

The largest minimal non-single-digit prime, i.e., a prime with greater than or equal to two digits such that deleting any number of its digits never gives another prime with greater than or equal to two digits. There are a total of 77 such primes. [Xayah]