256535591 has 8 divisors (see below), whose sum is σ = 277065600. Its totient is φ = 236119392.

The previous prime is 256535581. The next prime is 256535641. The reversal of 256535591 is 195535652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256535591 - 2¹⁸ = 256273447 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 (256535501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23735 + ... + 32808.

It is an arithmetic number, because the mean of its divisors is an integer number (34633200).

Almost surely, 2^256535591 is an apocalyptic number.

256535591 is a deficient number, since it is larger than the sum of its proper divisors (20530009).

256535591 is a wasteful number, since it uses less digits than its factorization.

256535591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56905.

The product of its digits is 202500, while the sum is 41.

The square root of 256535591 is about 16016.7284736927. The cubic root of 256535591 is about 635.4029236470.

The spelling of 256535591 in words is "two hundred fifty-six million, five hundred thirty-five thousand, five hundred ninety-one".