18049591 has 6 divisors (see below), whose sum is σ = 20996520. Its totient is φ = 15471036.

The previous prime is 18049583. The next prime is 18049607. The reversal of 18049591 is 19594081.

It is not a de Polignac number, because 18049591 - 2³ = 18049583 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 18049591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18049511) 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 5 ways as a sum of consecutive naturals, for example, 184131 + ... + 184228.

It is an arithmetic number, because the mean of its divisors is an integer number (3499420).

Almost surely, 2^18049591 is an apocalyptic number.

18049591 is a deficient number, since it is larger than the sum of its proper divisors (2946929).

18049591 is an equidigital number, since it uses as much as digits as its factorization.

18049591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368373 (or 368366 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 18049591 is about 4248.4810226715. The cubic root of 18049591 is about 262.3145950043.

The spelling of 18049591 in words is "eighteen million, forty-nine thousand, five hundred ninety-one".