59999...99999 (14564-digits)

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

6*10^14563-1-10^12267 is the smallest prime whose sum of digits is 131071, the sixth Mersenne prime. The sequence of such primes begin 3, 7, 4999, 299999989999999, 2(9)₄₉₂8(9)₄₁₇, 6*10^14563-1-10^12267, ... . [Gupta]