256571 has 4 divisors (see below), whose sum is σ = 293232. Its totient is φ = 219912.

The previous prime is 256567. The next prime is 256577. The reversal of 256571 is 175652.

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

It is not a de Polignac number, because 256571 - 2² = 256567 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 256571.

It is not an unprimeable number, because it can be changed into a prime (256577) 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, 18320 + ... + 18333.

It is an arithmetic number, because the mean of its divisors is an integer number (73308).

2²⁵⁶⁵⁷¹ is an apocalyptic number.

256571 is a deficient number, since it is larger than the sum of its proper divisors (36661).

256571 is an equidigital number, since it uses as much as digits as its factorization.

256571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36660.

The product of its digits is 2100, while the sum is 26.

The square root of 256571 is about 506.5283802513. The cubic root of 256571 is about 63.5432156689.

The spelling of 256571 in words is "two hundred fifty-six thousand, five hundred seventy-one".