18044391 has 12 divisors (see below), whose sum is σ = 24639288. Its totient is φ = 11746224.

The previous prime is 18044353. The next prime is 18044399. The reversal of 18044391 is 19344081.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-18044391 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18044399) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3921 + ... + 7173.

It is an arithmetic number, because the mean of its divisors is an integer number (2053274).

Almost surely, 2^18044391 is an apocalyptic number.

18044391 is a deficient number, since it is larger than the sum of its proper divisors (6594897).

18044391 is an equidigital number, since it uses as much as digits as its factorization.

18044391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3342 (or 3299 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 18044391 is about 4247.8689951551. The cubic root of 18044391 is about 262.2894020622.

The spelling of 18044391 in words is "eighteen million, forty-four thousand, three hundred ninety-one".