18665872 has 10 divisors (see below), whose sum is σ = 36165158. Its totient is φ = 9332928.

The previous prime is 18665869. The next prime is 18665873. The reversal of 18665872 is 27856681.

It can be written as a sum of positive squares in only one way, i.e., 14017536 + 4648336 = 3744^2 + 2156^2 .

It is not an unprimeable number, because it can be changed into a prime (18665873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583293 + ... + 583324.

Almost surely, 2^18665872 is an apocalyptic number.

It is an amenable number.

18665872 is a deficient number, since it is larger than the sum of its proper divisors (17499286).

18665872 is a wasteful number, since it uses less digits than its factorization.

18665872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166625 (or 1166619 counting only the distinct ones).

The product of its digits is 161280, while the sum is 43.

The square root of 18665872 is about 4320.4018331632. The cubic root of 18665872 is about 265.2667161586.

The spelling of 18665872 in words is "eighteen million, six hundred sixty-five thousand, eight hundred seventy-two".