256506 has 8 divisors (see below), whose sum is σ = 513024. Its totient is φ = 85500.

The previous prime is 256499. The next prime is 256517. The reversal of 256506 is 605652.

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

256506 is an admirable number.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 256506.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 21370 + ... + 21381.

It is an arithmetic number, because the mean of its divisors is an integer number (64128).

2²⁵⁶⁵⁰⁶ is an apocalyptic number.

256506 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256506 is a wasteful number, since it uses less digits than its factorization.

256506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42756.

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 256506 is about 506.4642139382. The cubic root of 256506 is about 63.5378491779.

The spelling of 256506 in words is "two hundred fifty-six thousand, five hundred six".