81320893 has 16 divisors (see below), whose sum is σ = 89740800. Its totient is φ = 73347120.

The previous prime is 81320891. The next prime is 81320909. The reversal of 81320893 is 39802318.

It is a cyclic number.

It is not a de Polignac number, because 81320893 - 2¹ = 81320891 is a prime.

It is a super-2 number, since 2×81320893² = 13226175276634898, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81320891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 165378 + ... + 165868.

It is an arithmetic number, because the mean of its divisors is an integer number (5608800).

Almost surely, 2^81320893 is an apocalyptic number.

It is an amenable number.

81320893 is a deficient number, since it is larger than the sum of its proper divisors (8419907).

81320893 is a wasteful number, since it uses less digits than its factorization.

81320893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 81320893 is about 9017.8097673437. The cubic root of 81320893 is about 433.2454858741.

The spelling of 81320893 in words is "eighty-one million, three hundred twenty thousand, eight hundred ninety-three".