81323533 has 8 divisors (see below), whose sum is σ = 82624256. Its totient is φ = 80028000.

The previous prime is 81323503. The next prime is 81323549. The reversal of 81323533 is 33532318.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81323533 - 2²⁵ = 47769101 is a prime.

It is a super-2 number, since 2×81323533² = 13227034039204178, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81323503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40708 + ... + 42658.

It is an arithmetic number, because the mean of its divisors is an integer number (10328032).

Almost surely, 2^81323533 is an apocalyptic number.

It is an amenable number.

81323533 is a deficient number, since it is larger than the sum of its proper divisors (1300723).

81323533 is a wasteful number, since it uses less digits than its factorization.

81323533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2595.

The product of its digits is 6480, while the sum is 28.

The square root of 81323533 is about 9017.9561431624. The cubic root of 81323533 is about 433.2501741146.

The spelling of 81323533 in words is "eighty-one million, three hundred twenty-three thousand, five hundred thirty-three".