256086591 has 4 divisors (see below), whose sum is σ = 341448792. Its totient is φ = 170724392.

The previous prime is 256086557. The next prime is 256086613. The reversal of 256086591 is 195680652.

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 256086591 - 2⁶ = 256086527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256087591) 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, 42681096 + ... + 42681101.

It is an arithmetic number, because the mean of its divisors is an integer number (85362198).

Almost surely, 2^256086591 is an apocalyptic number.

256086591 is a deficient number, since it is larger than the sum of its proper divisors (85362201).

256086591 is an equidigital number, since it uses as much as digits as its factorization.

256086591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85362200.

The product of its (nonzero) digits is 129600, while the sum is 42.

The square root of 256086591 is about 16002.7057399679. The cubic root of 256086591 is about 635.0320036777.

The spelling of 256086591 in words is "two hundred fifty-six million, eighty-six thousand, five hundred ninety-one".