990377764891511

This number is a prime.

                                                            99037 7764891511

The start of a prime quadruplet such that the sum of any three is prime. The four sums produce a second prime quadruplet starting at 2971133294674541. The sum of any three of those produce a third prime quadruplet starting at 8913399884023631. This is the smallest such quadruplet chain. [Andersen]