8640239 has 4 divisors (see below), whose sum is σ = 8681400. Its totient is φ = 8599080.

The previous prime is 8640221. The next prime is 8640241. The reversal of 8640239 is 9320468.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8640239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8640259) 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, 20264 + ... + 20685.

It is an arithmetic number, because the mean of its divisors is an integer number (2170350).

Almost surely, 2^8640239 is an apocalyptic number.

8640239 is a deficient number, since it is larger than the sum of its proper divisors (41161).

8640239 is a wasteful number, since it uses less digits than its factorization.

8640239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41160.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 8640239 is about 2939.4283457843. The cubic root of 8640239 is about 205.1990056405.

The spelling of 8640239 in words is "eight million, six hundred forty thousand, two hundred thirty-nine".