12844...65477 (77-digits)

This number is a prime.

                                                                     1284420
5165381031 4916622590 2897755319 8964984323 9158643682 1617764704 3137765477

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One of the prime factors of the 155-digit RSA modulus used by Simon Singh in Stage 10 of the Cipher Challenge in "The Code Book." It was discovered on 5 October 2000 by Fredrik Almgren, Gunnar Anderson, Torbjorn Granlund, Lars Ivansson, and Staffan Ulfberg, in Stockholm, Sweden. [Necula]