81320331 has 8 divisors (see below), whose sum is σ = 108473344. Its totient is φ = 54190440.

The previous prime is 81320311. The next prime is 81320359. The reversal of 81320331 is 13302318.

It is a happy number.

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

It is not a de Polignac number, because 81320331 - 2¹¹ = 81318283 is a prime.

It is a super-2 number, since 2×81320331² = 13225992467899122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81320298 and 81320307.

It is not an unprimeable number, because it can be changed into a prime (81320311) 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, 5670 + ... + 13956.

It is an arithmetic number, because the mean of its divisors is an integer number (13559168).

Almost surely, 2^81320331 is an apocalyptic number.

81320331 is a deficient number, since it is larger than the sum of its proper divisors (27153013).

81320331 is a wasteful number, since it uses less digits than its factorization.

81320331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11561.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 81320331 is about 9017.7786067302. The cubic root of 81320331 is about 433.2444878341.

Adding to 81320331 its reverse (13302318), we get a palindrome (94622649).

The spelling of 81320331 in words is "eighty-one million, three hundred twenty thousand, three hundred thirty-one".