At 663 bits, RSA-200 is the largest RSA Challenge Number factored to date.
The sieving effort is estimated to have taken the equivalent of 55 years on a single 2.2 GHz Opteron CPU. The matrix step reportedly took about 3 months on a cluster of 80 2.2 GHz Opterons. The sieving began in late 2003 and the matrix step was completed in May 2005. P. Montgomery and H. te Riele at the CWI, and F. Bahr and his family also contributed to the project.
University of Bonn, CWI and BSI provided computing resources.
MIPS-years estimates were not immediately available.
Please see Paul Zimmermann's factoring page for more information.