81330306 has 16 divisors (see below), whose sum is σ = 166628448. Its totient is φ = 26448800.

The previous prime is 81330299. The next prime is 81330307. The reversal of 81330306 is 60303318.

It is a super-2 number, since 2×81330306² = 13229237348107272, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81330307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165060 + ... + 165551.

It is an arithmetic number, because the mean of its divisors is an integer number (10414278).

Almost surely, 2^81330306 is an apocalyptic number.

81330306 is an abundant number, since it is smaller than the sum of its proper divisors (85298142).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81330306 is a wasteful number, since it uses less digits than its factorization.

81330306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330657.

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 81330306 is about 9018.3316638944. The cubic root of 81330306 is about 433.2622014736.

The spelling of 81330306 in words is "eighty-one million, three hundred thirty thousand, three hundred six".