Expression : $$N = \sqrt{25^{64} \times 64^{25}}$$
= $$\sqrt{(5)^{128}\times(2)^{150}}$$
= $$(5)^{64}\times(2)^{75}$$
= $$(2)^{11}\times(10)^{64}$$
= $$2048\times(10)^{64}$$
Thus, there are 68 digits in the numbers and sum of digits = $$2+0+4+8=14$$
=> Ans - (C)