39807...83317 (87-digits)

This number is a prime.

                                                          3980750 8642406493
7397125500 5503864911 9906436234 2526708406 3851895759 4638895726 1768583317

The smallest prime factor for the RSA challenge number RSA-576. Discovered by J. Franke, et al. [Sladcik]