Answer
$3.57\times10^{16}kg$
Work Step by Step
The Schwarzschild radius is given on page 963: $\frac{2GM}{c^2}$.
Solve for the mass: $M=\frac{Rc^2}{2G}$
$$M=\frac{(5.29\times10^{-11}m)(3.00\times10^8m/s)^2}{2(6.67\times10^{-11}Nm^2/kg^2) } $$
$$=3.57\times10^{16}kg $$
