256101591 has 4 divisors (see below), whose sum is σ = 341468792. Its totient is φ = 170734392.

The previous prime is 256101557. The next prime is 256101623. The reversal of 256101591 is 195101652.

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

It is not a de Polignac number, because 256101591 - 2¹³ = 256093399 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 (256101541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42683596 + ... + 42683601.

It is an arithmetic number, because the mean of its divisors is an integer number (85367198).

Almost surely, 2^256101591 is an apocalyptic number.

256101591 is a deficient number, since it is larger than the sum of its proper divisors (85367201).

256101591 is an equidigital number, since it uses as much as digits as its factorization.

256101591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85367200.

The product of its (nonzero) digits is 2700, while the sum is 30.

The square root of 256101591 is about 16003.1744038488. The cubic root of 256101591 is about 635.0444022106.

The spelling of 256101591 in words is "two hundred fifty-six million, one hundred one thousand, five hundred ninety-one".