256555 has 8 divisors (see below), whose sum is σ = 331632. Its totient is φ = 189408.

The previous prime is 256541. The next prime is 256561. The reversal of 256555 is 555652.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256555 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1909 + ... + 2038.

It is an arithmetic number, because the mean of its divisors is an integer number (41454).

2²⁵⁶⁵⁵⁵ is an apocalyptic number.

256555 is a deficient number, since it is larger than the sum of its proper divisors (75077).

256555 is a wasteful number, since it uses less digits than its factorization.

256555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3965.

The product of its digits is 7500, while the sum is 28.

The square root of 256555 is about 506.5125862207. The cubic root of 256555 is about 63.5418947706.

The spelling of 256555 in words is "two hundred fifty-six thousand, five hundred fifty-five".