18406399 has 8 divisors (see below), whose sum is σ = 20247120. Its totient is φ = 16731880.

The previous prime is 18406379. The next prime is 18406471. The reversal of 18406399 is 99360481.

It is not a de Polignac number, because 18406399 - 2¹³ = 18398207 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18406319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5584 + ... + 8245.

It is an arithmetic number, because the mean of its divisors is an integer number (2530890).

Almost surely, 2^18406399 is an apocalyptic number.

18406399 is a deficient number, since it is larger than the sum of its proper divisors (1840721).

18406399 is an equidigital number, since it uses as much as digits as its factorization.

18406399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13862 (or 13840 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 18406399 is about 4290.2679403506. The cubic root of 18406399 is about 264.0318248671.

The spelling of 18406399 in words is "eighteen million, four hundred six thousand, three hundred ninety-nine".