18083991 has 8 divisors (see below), whose sum is σ = 25381120. Its totient is φ = 11421432.

The previous prime is 18083987. The next prime is 18084013. The reversal of 18083991 is 19938081.

It is a happy number.

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

It is not a de Polignac number, because 18083991 - 2² = 18083987 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 (18083921) 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, 158575 + ... + 158688.

It is an arithmetic number, because the mean of its divisors is an integer number (3172640).

Almost surely, 2^18083991 is an apocalyptic number.

18083991 is a deficient number, since it is larger than the sum of its proper divisors (7297129).

18083991 is a wasteful number, since it uses less digits than its factorization.

18083991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317285.

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 18083991 is about 4252.5276013214. The cubic root of 18083991 is about 262.4811342451.

The spelling of 18083991 in words is "eighteen million, eighty-three thousand, nine hundred ninety-one".