81321443331 has 8 divisors (see below), whose sum is σ = 108973459200. Its totient is φ = 53941861512.

The previous prime is 81321443327. The next prime is 81321443341. The reversal of 81321443331 is 13334412318.

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 81321443331 - 2² = 81321443327 is a prime.

It is a super-2 number, since 2×81321443331² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81321443292 and 81321443301.

It is not an unprimeable number, because it can be changed into a prime (81321443341) 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, 68107815 + ... + 68109008.

It is an arithmetic number, because the mean of its divisors is an integer number (13621682400).

Almost surely, 2^81321443331 is an apocalyptic number.

81321443331 is a deficient number, since it is larger than the sum of its proper divisors (27652015869).

81321443331 is a wasteful number, since it uses less digits than its factorization.

81321443331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136217025.

The product of its digits is 20736, while the sum is 33.

Adding to 81321443331 its reverse (13334412318), we get a palindrome (94655855649).

The spelling of 81321443331 in words is "eighty-one billion, three hundred twenty-one million, four hundred forty-three thousand, three hundred thirty-one".