Finding equilibrium constant from standard free energy
Your problem seems to be one of calculation using large numbers, so look at it this way:
$$
\ln K = 1161.93596
$$
So
$$
\log_{10}K = \ln K \log_{10}(e) = 504.65\\
\Rightarrow K = 10^{504.65} = 10^{0.65}\times 10^{504} = 4.5 \times 10^{504}
$$
without your calculator exploding.