81079822931 has 4 divisors (see below), whose sum is σ = 81084909264. Its totient is φ = 81074736600.

The previous prime is 81079822909. The next prime is 81079822969. The reversal of 81079822931 is 13922897018.

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

It is a cyclic number.

It is not a de Polignac number, because 81079822931 - 2¹⁸ = 81079560787 is a prime.

It is a super-2 number, since 2×81079822931² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81079822931.

It is not an unprimeable number, because it can be changed into a prime (81079822331) 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, 2519180 + ... + 2551161.

It is an arithmetic number, because the mean of its divisors is an integer number (20271227316).

Almost surely, 2^81079822931 is an apocalyptic number.

81079822931 is a deficient number, since it is larger than the sum of its proper divisors (5086333).

81079822931 is a wasteful number, since it uses less digits than its factorization.

81079822931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5086332.

The product of its (nonzero) digits is 435456, while the sum is 50.

The spelling of 81079822931 in words is "eighty-one billion, seventy-nine million, eight hundred twenty-two thousand, nine hundred thirty-one".