18138056691 has 8 divisors (see below), whose sum is σ = 24228289984. Its totient is φ = 12069930600.

The previous prime is 18138056683. The next prime is 18138056737. The reversal of 18138056691 is 19665083181.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18138056691 - 2³ = 18138056683 is a prime.

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 18138056691.

It is not an unprimeable number, because it can be changed into a prime (18138056681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5524885 + ... + 5528166.

It is an arithmetic number, because the mean of its divisors is an integer number (3028536248).

Almost surely, 2^18138056691 is an apocalyptic number.

18138056691 is a deficient number, since it is larger than the sum of its proper divisors (6090233293).

18138056691 is a wasteful number, since it uses less digits than its factorization.

18138056691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11053601.

The product of its (nonzero) digits is 311040, while the sum is 48.

The spelling of 18138056691 in words is "eighteen billion, one hundred thirty-eight million, fifty-six thousand, six hundred ninety-one".