18103391 has 4 divisors (see below), whose sum is σ = 18263712. Its totient is φ = 17943072.

The previous prime is 18103373. The next prime is 18103433. The reversal of 18103391 is 19330181.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18103391 - 2¹⁴ = 18087007 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 18103391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18103331) 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 3 ways as a sum of consecutive naturals, for example, 79991 + ... + 80216.

It is an arithmetic number, because the mean of its divisors is an integer number (4565928).

Almost surely, 2^18103391 is an apocalyptic number.

18103391 is a deficient number, since it is larger than the sum of its proper divisors (160321).

18103391 is a wasteful number, since it uses less digits than its factorization.

18103391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160320.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 18103391 is about 4254.8079862668. The cubic root of 18103391 is about 262.5749615090.

The spelling of 18103391 in words is "eighteen million, one hundred three thousand, three hundred ninety-one".