18949903 has 4 divisors (see below), whose sum is σ = 21657040. Its totient is φ = 16242768.

The previous prime is 18949877. The next prime is 18949949. The reversal of 18949903 is 30994981.

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 18949903 - 2⁹ = 18949391 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 18949903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18949993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1353558 + ... + 1353571.

It is an arithmetic number, because the mean of its divisors is an integer number (5414260).

Almost surely, 2^18949903 is an apocalyptic number.

18949903 is a deficient number, since it is larger than the sum of its proper divisors (2707137).

18949903 is an equidigital number, since it uses as much as digits as its factorization.

18949903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2707136.

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 18949903 is about 4353.1486305891. The cubic root of 18949903 is about 266.6054340310.

The spelling of 18949903 in words is "eighteen million, nine hundred forty-nine thousand, nine hundred three".