For a cell reaction with $E^\circ_\text{cell} = +0.59\,\text{V}$ and $n = 2$, the equilibrium constant $K$ at $298\,\text{K}$ is approximately:

At equilibrium $E_\text{cell} = 0$, so the Nernst equation gives $\log K = \dfrac{n E^\circ_\text{cell}}{0.0591} = \dfrac{2 \times 0.59}{0.0591} \approx 20$. Hence $K \approx 10^{20}$. Large positive $E^\circ_\text{cell}$ values therefore correspond to overwhelmingly product-favoured equilibria.