If log 2 = 0.30103, the number of digits in 2⁶⁴ is:

Solution (By Examveda Team)

$$\eqalign{ & \log \left( {{2^{64}}} \right) \cr & = 64 \times \log 2 \cr & = \left( {64 \times 0.30103} \right) \cr & = 19.26592 \cr} $$
Its characteristic is 19.
Hence, then number of digits in 2⁶⁴ is 20.