256005 has 12 divisors (see below), whose sum is σ = 443820. Its totient is φ = 136512.

The previous prime is 255989. The next prime is 256019. The reversal of 256005 is 500652.

It can be written as a sum of positive squares in 2 ways, for example, as 181476 + 74529 = 426^2 + 273^2 .

It is not a de Polignac number, because 256005 - 2⁴ = 255989 is a prime.

It is a Curzon number.

It is a zygodrome in base 4.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2800 + ... + 2889.

It is an arithmetic number, because the mean of its divisors is an integer number (36985).

2²⁵⁶⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

256005 is a deficient number, since it is larger than the sum of its proper divisors (187815).

256005 is a wasteful number, since it uses less digits than its factorization.

256005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5700 (or 5697 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 256005 is about 505.9693666617. The cubic root of 256005 is about 63.4964554617.

Adding to 256005 its reverse (500652), we get a palindrome (756657).

The spelling of 256005 in words is "two hundred fifty-six thousand, five".