The article deals with factoring cryptanalysis that can be used in attack on popular encryption and digital signing algorithm RSA. Factoring reduces to SAT problem, and one's solution is unique and corresponds to multiplier's bit. A method of simple iteration is applied to SAT, also three polynomial heuristics are applied with the goal to improve convergence. Also it describes alternative method of solving SAT based on constructing system of linear equations and it's solution by Gauss-Zeidel method. The statistics of each SAT component's correct recognition is formed after numerical experiments. The obtained data is used in hybrid with famous local-search algorithm GSAT for attack RSA algorithm.