18490991 has 8 divisors (see below), whose sum is σ = 18976464. Its totient is φ = 18011520.

The previous prime is 18490987. The next prime is 18490999. The reversal of 18490991 is 19909481.

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

It is a cyclic number.

It is not a de Polignac number, because 18490991 - 2² = 18490987 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 (18490999) 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, 5111 + ... + 7943.

It is an arithmetic number, because the mean of its divisors is an integer number (2372058).

Almost surely, 2^18490991 is an apocalyptic number.

18490991 is a deficient number, since it is larger than the sum of its proper divisors (485473).

18490991 is a wasteful number, since it uses less digits than its factorization.

18490991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3001.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 18490991 is about 4300.1152310142. The cubic root of 18490991 is about 264.4356853501.

The spelling of 18490991 in words is "eighteen million, four hundred ninety thousand, nine hundred ninety-one".