Answer
$3^{4}$
Work Step by Step
In order to find the prime factorization by 81, we can try to divide 81 by the first prime number, 2.
81 is not divisible by 2, so we can divide it by the next prime, 3.
$81\div3=27$
27 is not divisible by 2, so we can divide by 3.
$27\div3=9$
9 is not divisible by 2, so we can divide by 3.
$9\div3=3$
The number 3 itself is a prime number. Therefore, the prime factorization of 81 is $3\times3\times3\times3=3^{4}$.
