81320868 has 48 divisors (see below), whose sum is σ = 214824960. Its totient is φ = 26593632.

The previous prime is 81320807. The next prime is 81320873. The reversal of 81320868 is 86802318.

It is a super-2 number, since 2×81320868² = 13226167144546848, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1380 + ... + 12827.

It is an arithmetic number, because the mean of its divisors is an integer number (4475520).

Almost surely, 2^81320868 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81320868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107412480).

81320868 is an abundant number, since it is smaller than the sum of its proper divisors (133504092).

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

81320868 is a wasteful number, since it uses less digits than its factorization.

81320868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14273 (or 14265 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 81320868 is about 9017.8083811977. The cubic root of 81320868 is about 433.2454414774.

The spelling of 81320868 in words is "eighty-one million, three hundred twenty thousand, eight hundred sixty-eight".