81320 has 32 divisors (see below), whose sum is σ = 194400. Its totient is φ = 30528.

The previous prime is 81307. The next prime is 81331. The reversal of 81320 is 2318.

81320 = 6² + 7² + ... + 62².

It is a super-2 number, since 2×81320² = 13225884800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81295 and 81304.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 707 + ... + 813.

It is an arithmetic number, because the mean of its divisors is an integer number (6075).

2⁸¹³²⁰ 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 81320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97200).

81320 is an abundant number, since it is smaller than the sum of its proper divisors (113080).

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

81320 is a wasteful number, since it uses less digits than its factorization.

81320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 81320 is about 285.1666179622. The cubic root of 81320 is about 43.3243900018.

Adding to 81320 its reverse (2318), we get a palindrome (83638).

The spelling of 81320 in words is "eighty-one thousand, three hundred twenty".