256997 has 8 divisors (see below), whose sum is σ = 282744. Its totient is φ = 232128.

The previous prime is 256981. The next prime is 257003. The reversal of 256997 is 799652.

It can be written as a sum of positive squares in 4 ways, for example, as 27556 + 229441 = 166^2 + 479^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 256997 - 2⁴ = 256981 is a prime.

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 256997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 503 + ... + 875.

It is an arithmetic number, because the mean of its divisors is an integer number (35343).

2²⁵⁶⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

256997 is a deficient number, since it is larger than the sum of its proper divisors (25747).

256997 is a wasteful number, since it uses less digits than its factorization.

256997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439.

The product of its digits is 34020, while the sum is 38.

The square root of 256997 is about 506.9487153549. The cubic root of 256997 is about 63.5783644088.

The spelling of 256997 in words is "two hundred fifty-six thousand, nine hundred ninety-seven".