How many digits are there in the number N=213⋅59N = 2^{13} · 5^9N=213⋅59? Solution N=213⋅59=24⋅29⋅59=24⋅109=16⋅109=1.6⋅1010N = 2^{13} · 5^9 = 2^4 · 2^9 · 5^9 = 2^4 · 10^9 = 16 · 10^9 = 1.6 \cdot 10^{10}N=213⋅59=24⋅29⋅59=24⋅109=16⋅109=1.6⋅1010, which has 111111 digits.