256704399 has 24 divisors (see below), whose sum is σ = 424366592. Its totient is φ = 146480400.

The previous prime is 256704377. The next prime is 256704401. The reversal of 256704399 is 993407652.

It is a happy number.

256704399 is a `hidden beast` number, since 256 + 7 + 0 + 4 + 399 = 666.

It is not a de Polignac number, because 256704399 - 2²⁰ = 255655823 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256704319) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49374 + ... + 54324.

Almost surely, 2^256704399 is an apocalyptic number.

256704399 is a deficient number, since it is larger than the sum of its proper divisors (167662193).

256704399 is a wasteful number, since it uses less digits than its factorization.

256704399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5787 (or 5784 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 45.

The square root of 256704399 is about 16021.9973473971. The cubic root of 256704399 is about 635.5422643884.

The spelling of 256704399 in words is "two hundred fifty-six million, seven hundred four thousand, three hundred ninety-nine".