640233565 has 4 divisors (see below), whose sum is σ = 768280284. Its totient is φ = 512186848.

The previous prime is 640233547. The next prime is 640233571. The reversal of 640233565 is 565332046.

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 92813956 + 547419609 = 9634^2 + 23397^2 .

It is a cyclic number.

It is not a de Polignac number, because 640233565 - 2⁷ = 640233437 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640233565.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64023352 + ... + 64023361.

It is an arithmetic number, because the mean of its divisors is an integer number (192070071).

Almost surely, 2^640233565 is an apocalyptic number.

It is an amenable number.

640233565 is a deficient number, since it is larger than the sum of its proper divisors (128046719).

640233565 is a wasteful number, since it uses less digits than its factorization.

640233565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128046718.

The product of its (nonzero) digits is 64800, while the sum is 34.

The square root of 640233565 is about 25302.8370938913. The cubic root of 640233565 is about 861.8786967080.

The spelling of 640233565 in words is "six hundred forty million, two hundred thirty-three thousand, five hundred sixty-five".