81081130631 has 4 divisors (see below), whose sum is σ = 81086949792. Its totient is φ = 81075311472.

The previous prime is 81081130621. The next prime is 81081130657. The reversal of 81081130631 is 13603118018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81081130631 is a prime.

It is a super-2 number, since 2×81081130631² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81081130601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2888630 + ... + 2916563.

It is an arithmetic number, because the mean of its divisors is an integer number (20271737448).

Almost surely, 2^81081130631 is an apocalyptic number.

81081130631 is a deficient number, since it is larger than the sum of its proper divisors (5819161).

81081130631 is a wasteful number, since it uses less digits than its factorization.

81081130631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5819160.

The product of its (nonzero) digits is 3456, while the sum is 32.

Adding to 81081130631 its reverse (13603118018), we get a palindrome (94684248649).

The spelling of 81081130631 in words is "eighty-one billion, eighty-one million, one hundred thirty thousand, six hundred thirty-one".