16180...31361 (255-digits)

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

                           16180 3398874989 4848204586 8343656381 1772030917
9805762862 1354486227 0526046281 8902449707 2072041893 9113748475 4088075386
8917521266 3386222353 6931793180 0607667263 5443338908 6595939582 9056383226
6131992829 0267880675 2087668925 0171169620 7032221043 2162695486 2629631361

The number formed from the decimal expansion (first 255 digits) of the golden ratio is an emirp. [Petrov]