18268639 has 4 divisors (see below), whose sum is σ = 18762424. Its totient is φ = 17774856.

The previous prime is 18268619. The next prime is 18268643. The reversal of 18268639 is 93686281.

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

It is a cyclic number.

It is not a de Polignac number, because 18268639 - 2¹³ = 18260447 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18268595 and 18268604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18268609) 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, 246837 + ... + 246910.

It is an arithmetic number, because the mean of its divisors is an integer number (4690606).

Almost surely, 2^18268639 is an apocalyptic number.

18268639 is a deficient number, since it is larger than the sum of its proper divisors (493785).

18268639 is an equidigital number, since it uses as much as digits as its factorization.

18268639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493784.

The product of its digits is 124416, while the sum is 43.

The square root of 18268639 is about 4274.1828458783. The cubic root of 18268639 is about 263.3714721595.

The spelling of 18268639 in words is "eighteen million, two hundred sixty-eight thousand, six hundred thirty-nine".