256404663 has 16 divisors (see below), whose sum is σ = 380640000. Its totient is φ = 170584920.

The previous prime is 256404653. The next prime is 256404671. The reversal of 256404663 is 366404652.

256404663 is a `hidden beast` number, since 2 + 5 + 640 + 4 + 6 + 6 + 3 = 666.

It is not a de Polignac number, because 256404663 - 2⁴ = 256404647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256404623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3958 + ... + 22988.

It is an arithmetic number, because the mean of its divisors is an integer number (23790000).

Almost surely, 2^256404663 is an apocalyptic number.

256404663 is a deficient number, since it is larger than the sum of its proper divisors (124235337).

256404663 is a wasteful number, since it uses less digits than its factorization.

256404663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19539 (or 19533 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 256404663 is about 16012.6407253769. The cubic root of 256404663 is about 635.2948084461.

It can be divided in two parts, 25640 and 4663, that added together give a palindrome (30303).

The spelling of 256404663 in words is "two hundred fifty-six million, four hundred four thousand, six hundred sixty-three".