256340647 has 4 divisors (see below), whose sum is σ = 269832280. Its totient is φ = 242849016.

The previous prime is 256340629. The next prime is 256340677. The reversal of 256340647 is 746043652.

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

It is a cyclic number.

It is not a de Polignac number, because 256340647 - 2¹⁹ = 255816359 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 (256340627) 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, 6745788 + ... + 6745825.

It is an arithmetic number, because the mean of its divisors is an integer number (67458070).

Almost surely, 2^256340647 is an apocalyptic number.

256340647 is a deficient number, since it is larger than the sum of its proper divisors (13491633).

256340647 is a wasteful number, since it uses less digits than its factorization.

256340647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13491632.

The product of its (nonzero) digits is 120960, while the sum is 37.

The square root of 256340647 is about 16010.6416798328. The cubic root of 256340647 is about 635.2419331499.

The spelling of 256340647 in words is "two hundred fifty-six million, three hundred forty thousand, six hundred forty-seven".