18109903 has 4 divisors (see below), whose sum is σ = 20697040. Its totient is φ = 15522768.

The previous prime is 18109849. The next prime is 18109937. The reversal of 18109903 is 30990181.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18109903 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18109943) 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, 1293558 + ... + 1293571.

It is an arithmetic number, because the mean of its divisors is an integer number (5174260).

Almost surely, 2^18109903 is an apocalyptic number.

18109903 is a deficient number, since it is larger than the sum of its proper divisors (2587137).

18109903 is an equidigital number, since it uses as much as digits as its factorization.

18109903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2587136.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 18109903 is about 4255.5731693862. The cubic root of 18109903 is about 262.6064414891.

The spelling of 18109903 in words is "eighteen million, one hundred nine thousand, nine hundred three".