Main Page | See live article | Alphabetical index In mathematics, RSA-640 is one of the RSA numbers, large semiprimes that are part of the RSA Factoring Challenge. RSA-640 has a length of 193 decimal digits and has not been factored so far; a cash prize of $20,000 USD has been offered successful factorisation by RSA Security. RSA-640 = 31074182404900437213507500358885679300373460228427275457201619488232064405 18081504556346829671723286782437916272838033415471073108501919548529007337 724822783525742386454014691736602477652346609 External links RSA Factoring Challenge: RSA-640 This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.