What is 81 divisible by?

81 is a composite number that is divisible by 1, 3, 9, 27, and 81. It is a square of 9 and can also be expressed as 3 to the power of 4. Being a multiple of 9, any integer that is divisible by 81 must also be divisible by 9. Its prime factorization is 3 x 3 x 3 x 3. It is commonly used as a perfect square in mathematics and is often seen in equations involving area or volume.