42875...01401 (30986-digits)

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

As of February 2013, the largest known prime that can be expressed as RevDigits(2^n, 10), i.e., the reversal of 2^n in base 10 (case n = 102930). It was found by Giovanni Resta of Italy.