18665649 has 12 divisors (see below), whose sum is σ = 27690676. Its totient is φ = 12107232.

The previous prime is 18665639. The next prime is 18665651. The reversal of 18665649 is 94656681.

18665649 is a `hidden beast` number, since 1 + 86 + 6 + 564 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 16548624 + 2117025 = 4068^2 + 1455^2 .

It is not a de Polignac number, because 18665649 - 2⁸ = 18665393 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18665629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27694 + ... + 28359.

Almost surely, 2^18665649 is an apocalyptic number.

It is an amenable number.

18665649 is a deficient number, since it is larger than the sum of its proper divisors (9025027).

18665649 is a wasteful number, since it uses less digits than its factorization.

18665649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56096 (or 56093 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 18665649 is about 4320.3760253015. The cubic root of 18665649 is about 265.2656597794.

The spelling of 18665649 in words is "eighteen million, six hundred sixty-five thousand, six hundred forty-nine".