18406385 has 4 divisors (see below), whose sum is σ = 22087668. Its totient is φ = 14725104.

The previous prime is 18406379. The next prime is 18406471. The reversal of 18406385 is 58360481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58360481 = 3877 ⋅15053.

It can be written as a sum of positive squares in 2 ways, for example, as 12418576 + 5987809 = 3524^2 + 2447^2 .

It is a cyclic number.

It is not a de Polignac number, because 18406385 - 2⁴ = 18406369 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1840634 + ... + 1840643.

It is an arithmetic number, because the mean of its divisors is an integer number (5521917).

Almost surely, 2^18406385 is an apocalyptic number.

It is an amenable number.

18406385 is a deficient number, since it is larger than the sum of its proper divisors (3681283).

18406385 is an equidigital number, since it uses as much as digits as its factorization.

18406385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3681282.

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 18406385 is about 4290.2663087505. The cubic root of 18406385 is about 264.0317579258.

The spelling of 18406385 in words is "eighteen million, four hundred six thousand, three hundred eighty-five".