18112991 has 8 divisors (see below), whose sum is σ = 19553184. Its totient is φ = 16679520.

The previous prime is 18112957. The next prime is 18112993. The reversal of 18112991 is 19921181.

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

It is not a de Polignac number, because 18112991 - 2²² = 13918687 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 (18112993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4901 + ... + 7761.

It is an arithmetic number, because the mean of its divisors is an integer number (2444148).

Almost surely, 2^18112991 is an apocalyptic number.

18112991 is a deficient number, since it is larger than the sum of its proper divisors (1440193).

18112991 is a wasteful number, since it uses less digits than its factorization.

18112991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3361.

The product of its digits is 1296, while the sum is 32.

The square root of 18112991 is about 4255.9359722627. The cubic root of 18112991 is about 262.6213667044.

The spelling of 18112991 in words is "eighteen million, one hundred twelve thousand, nine hundred ninety-one".