81792522991 has 4 divisors (see below), whose sum is σ = 83178837000. Its totient is φ = 80406208984.

The previous prime is 81792522947. The next prime is 81792523037. The reversal of 81792522991 is 19922529718.

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 81792522991 - 2¹³ = 81792514799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81792522491) 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, 693156916 + ... + 693157033.

It is an arithmetic number, because the mean of its divisors is an integer number (20794709250).

Almost surely, 2^81792522991 is an apocalyptic number.

81792522991 is a deficient number, since it is larger than the sum of its proper divisors (1386314009).

81792522991 is a wasteful number, since it uses less digits than its factorization.

81792522991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1386314008.

The product of its digits is 1632960, while the sum is 55.

The spelling of 81792522991 in words is "eighty-one billion, seven hundred ninety-two million, five hundred twenty-two thousand, nine hundred ninety-one".