18439903 has 2 divisors, whose sum is σ = 18439904. Its totient is φ = 18439902.

The previous prime is 18439877. The next prime is 18439909. The reversal of 18439903 is 30993481.

It is a strong prime.

It is an emirp because it is prime and its reverse (30993481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18439903 - 2⁵ = 18439871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18439909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9219951 + 9219952.

It is an arithmetic number, because the mean of its divisors is an integer number (9219952).

Almost surely, 2^18439903 is an apocalyptic number.

18439903 is a deficient number, since it is larger than the sum of its proper divisors (1).

18439903 is an equidigital number, since it uses as much as digits as its factorization.

18439903 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 18439903 is about 4294.1708163509. The cubic root of 18439903 is about 264.1919278895.

The spelling of 18439903 in words is "eighteen million, four hundred thirty-nine thousand, nine hundred three".