57777...77777 (993-digits)

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

Just showing those entries submitted by 'Bajpai': (Click here to show all)

The largest non-titanic near-repdigit prime-digit prime p whose sum of digits (sod) is also prime. Curiously, p and sod(p) both can also be expressed as sum of two squares. [Bajpai]