256407439 has 4 divisors (see below), whose sum is σ = 256516200. Its totient is φ = 256298680.

The previous prime is 256407401. The next prime is 256407443. The reversal of 256407439 is 934704652.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256407439 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 (256407449) 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 in 3 ways as a sum of consecutive naturals, for example, 50764 + ... + 55585.

It is an arithmetic number, because the mean of its divisors is an integer number (64129050).

Almost surely, 2^256407439 is an apocalyptic number.

256407439 is a deficient number, since it is larger than the sum of its proper divisors (108761).

256407439 is a wasteful number, since it uses less digits than its factorization.

256407439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108760.

The product of its (nonzero) digits is 181440, while the sum is 40.

The square root of 256407439 is about 16012.7274066600. The cubic root of 256407439 is about 635.2971011397.

The spelling of 256407439 in words is "two hundred fifty-six million, four hundred seven thousand, four hundred thirty-nine".