81791111677 has 4 divisors (see below), whose sum is σ = 89226667296. Its totient is φ = 74355556060.

The previous prime is 81791111617. The next prime is 81791111713. The reversal of 81791111677 is 77611119718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81791111677 - 2¹⁵ = 81791078909 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 81791111677.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81791111617) 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, 3717777793 + ... + 3717777814.

It is an arithmetic number, because the mean of its divisors is an integer number (22306666824).

Almost surely, 2^81791111677 is an apocalyptic number.

It is an amenable number.

81791111677 is a deficient number, since it is larger than the sum of its proper divisors (7435555619).

81791111677 is a wasteful number, since it uses less digits than its factorization.

81791111677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7435555618.

The product of its digits is 148176, while the sum is 49.

The spelling of 81791111677 in words is "eighty-one billion, seven hundred ninety-one million, one hundred eleven thousand, six hundred seventy-seven".