2861

This number is a prime.

The largest known prime number that cannot be expressed as the sum of 3 pentagonal numbers. [Capelle]

The smallest prime which prefixed by the concatenation of two perfect numbers. [Firoozbakht]

Magnus Carlsen once achieved a rating of 2861 (highest in chess history at the time).

Smallest prime that uses four distinct digits such that every different permutation of its digits is composite. [Vantieghem]