18398399 has 4 divisors (see below), whose sum is σ = 18438264. Its totient is φ = 18358536.

The previous prime is 18398353. The next prime is 18398417. The reversal of 18398399 is 99389381.

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 18398399 - 2⁸ = 18398143 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 (18398309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19232 + ... + 20165.

It is an arithmetic number, because the mean of its divisors is an integer number (4609566).

Almost surely, 2^18398399 is an apocalyptic number.

18398399 is a deficient number, since it is larger than the sum of its proper divisors (39865).

18398399 is an equidigital number, since it uses as much as digits as its factorization.

18398399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39864.

The product of its digits is 419904, while the sum is 50.

The square root of 18398399 is about 4289.3354963211. The cubic root of 18398399 is about 263.9935671451.

The spelling of 18398399 in words is "eighteen million, three hundred ninety-eight thousand, three hundred ninety-nine".