256663 has 4 divisors (see below), whose sum is σ = 280008. Its totient is φ = 233320.

The previous prime is 256661. The next prime is 256687. The reversal of 256663 is 366652.

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

It is a cyclic number.

It is not a de Polignac number, because 256663 - 2¹ = 256661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11656 + ... + 11677.

It is an arithmetic number, because the mean of its divisors is an integer number (70002).

2²⁵⁶⁶⁶³ is an apocalyptic number.

256663 is a deficient number, since it is larger than the sum of its proper divisors (23345).

256663 is a wasteful number, since it uses less digits than its factorization.

256663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23344.

The product of its digits is 6480, while the sum is 28.

The square root of 256663 is about 506.6191863718. The cubic root of 256663 is about 63.5508097686.

It can be divided in two parts, 256 and 663, that added together give a palindrome (919).

The spelling of 256663 in words is "two hundred fifty-six thousand, six hundred sixty-three".