18087385 has 4 divisors (see below), whose sum is σ = 21704868. Its totient is φ = 14469904.

The previous prime is 18087347. The next prime is 18087389. The reversal of 18087385 is 58378081.

18087385 = T₃₄₇₁ + T₃₄₇₂ + T₃₄₇₃.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7038409 + 11048976 = 2653^2 + 3324^2 .

It is a cyclic number.

It is not a de Polignac number, because 18087385 - 2¹⁹ = 17563097 is a prime.

It is a super-2 number, since 2×18087385² = 654306992276450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18087389) 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, 1808734 + ... + 1808743.

It is an arithmetic number, because the mean of its divisors is an integer number (5426217).

Almost surely, 2^18087385 is an apocalyptic number.

18087385 is the 3473-rd centered triangular number.

It is an amenable number.

18087385 is a deficient number, since it is larger than the sum of its proper divisors (3617483).

18087385 is an equidigital number, since it uses as much as digits as its factorization.

18087385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3617482.

The product of its (nonzero) digits is 53760, while the sum is 40.

The square root of 18087385 is about 4252.9266393861. The cubic root of 18087385 is about 262.4975540210.

The spelling of 18087385 in words is "eighteen million, eighty-seven thousand, three hundred eighty-five".