18999903 has 8 divisors (see below), whose sum is σ = 27281968. Its totient is φ = 11692224.

The previous prime is 18999889. The next prime is 18999913. The reversal of 18999903 is 30999981.

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

It is not a de Polignac number, because 18999903 - 2⁶ = 18999839 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 (18999913) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243550 + ... + 243627.

It is an arithmetic number, because the mean of its divisors is an integer number (3410246).

Almost surely, 2^18999903 is an apocalyptic number.

18999903 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

18999903 is a deficient number, since it is larger than the sum of its proper divisors (8282065).

18999903 is a wasteful number, since it uses less digits than its factorization.

18999903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487193.

The product of its (nonzero) digits is 157464, while the sum is 48.

The square root of 18999903 is about 4358.8878168634. The cubic root of 18999903 is about 266.8397107750.

The spelling of 18999903 in words is "eighteen million, nine hundred ninety-nine thousand, nine hundred three".