256397 has 4 divisors (see below), whose sum is σ = 258780. Its totient is φ = 254016.

The previous prime is 256393. The next prime is 256423. The reversal of 256397 is 793652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7396 + 249001 = 86^2 + 499^2 .

It is a cyclic number.

It is not a de Polignac number, because 256397 - 2² = 256393 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 256397.

It is not an unprimeable number, because it can be changed into a prime (256391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1022 + ... + 1247.

It is an arithmetic number, because the mean of its divisors is an integer number (64695).

2²⁵⁶³⁹⁷ is an apocalyptic number.

It is an amenable number.

256397 is a deficient number, since it is larger than the sum of its proper divisors (2383).

256397 is a wasteful number, since it uses less digits than its factorization.

256397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2382.

The product of its digits is 11340, while the sum is 32.

The square root of 256397 is about 506.3565937163. The cubic root of 256397 is about 63.5288479502.

The spelling of 256397 in words is "two hundred fifty-six thousand, three hundred ninety-seven".