18315685 has 4 divisors (see below), whose sum is σ = 21978828. Its totient is φ = 14652544.

The previous prime is 18315673. The next prime is 18315691. The reversal of 18315685 is 58651381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58651381 = 2269 ⋅25849.

It can be written as a sum of positive squares in 2 ways, for example, as 11519236 + 6796449 = 3394^2 + 2607^2 .

It is a cyclic number.

It is not a de Polignac number, because 18315685 - 2⁵ = 18315653 is a prime.

It is a Duffinian number.

It is a congruent 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, 1831564 + ... + 1831573.

It is an arithmetic number, because the mean of its divisors is an integer number (5494707).

Almost surely, 2^18315685 is an apocalyptic number.

It is an amenable number.

18315685 is a deficient number, since it is larger than the sum of its proper divisors (3663143).

18315685 is an equidigital number, since it uses as much as digits as its factorization.

18315685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3663142.

The product of its digits is 28800, while the sum is 37.

The square root of 18315685 is about 4279.6828153498. The cubic root of 18315685 is about 263.5973593254.

The spelling of 18315685 in words is "eighteen million, three hundred fifteen thousand, six hundred eighty-five".