18665642 has 4 divisors (see below), whose sum is σ = 27998466. Its totient is φ = 9332820.

The previous prime is 18665639. The next prime is 18665651. The reversal of 18665642 is 24656681.

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

It can be written as a sum of positive squares in only one way, i.e., 18653761 + 11881 = 4319^2 + 109^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18665596 and 18665605.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4666409 + ... + 4666412.

Almost surely, 2^18665642 is an apocalyptic number.

18665642 is a deficient number, since it is larger than the sum of its proper divisors (9332824).

18665642 is an equidigital number, since it uses as much as digits as its factorization.

18665642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9332823.

The product of its digits is 69120, while the sum is 38.

The square root of 18665642 is about 4320.3752151868. The cubic root of 18665642 is about 265.2656266194.

The spelling of 18665642 in words is "eighteen million, six hundred sixty-five thousand, six hundred forty-two".