18638965 has 4 divisors (see below), whose sum is σ = 22366764. Its totient is φ = 14911168.

The previous prime is 18638959. The next prime is 18638989. The reversal of 18638965 is 56983681.

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 14085009 + 4553956 = 3753^2 + 2134^2 .

It is a cyclic number.

It is not a de Polignac number, because 18638965 - 2³ = 18638957 is a prime.

It is a super-2 number, since 2×18638965² = 694822032542450, which contains 22 as substring.

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, 1863892 + ... + 1863901.

It is an arithmetic number, because the mean of its divisors is an integer number (5591691).

Almost surely, 2^18638965 is an apocalyptic number.

It is an amenable number.

18638965 is a deficient number, since it is larger than the sum of its proper divisors (3727799).

18638965 is an equidigital number, since it uses as much as digits as its factorization.

18638965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3727798.

The product of its digits is 311040, while the sum is 46.

The square root of 18638965 is about 4317.2867636978. The cubic root of 18638965 is about 265.1391935175.

The spelling of 18638965 in words is "eighteen million, six hundred thirty-eight thousand, nine hundred sixty-five".