256593 has 4 divisors (see below), whose sum is σ = 342128. Its totient is φ = 171060.

The previous prime is 256589. The next prime is 256603. The reversal of 256593 is 395652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 256593 - 2² = 256589 is a prime.

It is a D-number.

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 256593.

It is not an unprimeable number, because it can be changed into a prime (256093) 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, 42763 + ... + 42768.

It is an arithmetic number, because the mean of its divisors is an integer number (85532).

256593 is a Friedman number, since it can be written as (6^5*(9+2)-5)*3, using all its digits and the basic arithmetic operations.

2²⁵⁶⁵⁹³ is an apocalyptic number.

It is an amenable number.

256593 is a deficient number, since it is larger than the sum of its proper divisors (85535).

256593 is an equidigital number, since it uses as much as digits as its factorization.

256593 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85534.

The product of its digits is 8100, while the sum is 30.

The square root of 256593 is about 506.5500962393. The cubic root of 256593 is about 63.5450318144.

The spelling of 256593 in words is "two hundred fifty-six thousand, five hundred ninety-three".