What is 4 square root of 81 to the fifth power in exponential form

When changing from radical form to fractional exponents, remember these basic forms:

The nth root of a can be written as a fractional exponent with a raised to the reciprocal of that power.

is taken, it's raised to the 1/n power. When a power is raised to another power, you multiply the powers together, and so the m (otherwise written as m/1) and the 1/n are multiplied together.

Use fractions in the powers to indicate that the expression stands for a root or a radical.

Leave the exponent as 9/4. Don't write it as a mixed number.