256406865 has 48 divisors (see below), whose sum is σ = 485669184. Its totient is φ = 114744960.

The previous prime is 256406863. The next prime is 256406867. The reversal of 256406865 is 568604652.

256406865 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (256406863) and next prime (256406867).

It is not a de Polignac number, because 256406865 - 2¹ = 256406863 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256406863) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18162 + ... + 29028.

It is an arithmetic number, because the mean of its divisors is an integer number (10118108).

Almost surely, 2^256406865 is an apocalyptic number.

It is an amenable number.

256406865 is a deficient number, since it is larger than the sum of its proper divisors (229262319).

256406865 is a wasteful number, since it uses less digits than its factorization.

256406865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10910 (or 10899 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 42.

The square root of 256406865 is about 16012.7094834072. The cubic root of 256406865 is about 635.2966270754.

The spelling of 256406865 in words is "two hundred fifty-six million, four hundred six thousand, eight hundred sixty-five".