256813399 has 2 divisors, whose sum is σ = 256813400. Its totient is φ = 256813398.

The previous prime is 256813379. The next prime is 256813439. The reversal of 256813399 is 993318652.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256813399 - 2¹³ = 256805207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256813309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128406699 + 128406700.

It is an arithmetic number, because the mean of its divisors is an integer number (128406700).

Almost surely, 2^256813399 is an apocalyptic number.

256813399 is a deficient number, since it is larger than the sum of its proper divisors (1).

256813399 is an equidigital number, since it uses as much as digits as its factorization.

256813399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 349920, while the sum is 46.

The square root of 256813399 is about 16025.3985597863. The cubic root of 256813399 is about 635.6322048082.

The spelling of 256813399 in words is "two hundred fifty-six million, eight hundred thirteen thousand, three hundred ninety-nine".