256923857 has 4 divisors (see below), whose sum is σ = 258409140. Its totient is φ = 255438576.

The previous prime is 256923853. The next prime is 256923899. The reversal of 256923857 is 758329652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 180203776 + 76720081 = 13424^2 + 8759^2 .

It is a cyclic number.

It is not a de Polignac number, because 256923857 - 2² = 256923853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256923853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 742382 + ... + 742727.

It is an arithmetic number, because the mean of its divisors is an integer number (64602285).

Almost surely, 2^256923857 is an apocalyptic number.

It is an amenable number.

256923857 is a deficient number, since it is larger than the sum of its proper divisors (1485283).

256923857 is a wasteful number, since it uses less digits than its factorization.

256923857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1485282.

The product of its digits is 907200, while the sum is 47.

The square root of 256923857 is about 16028.8445310322. The cubic root of 256923857 is about 635.7233223260.

The spelling of 256923857 in words is "two hundred fifty-six million, nine hundred twenty-three thousand, eight hundred fifty-seven".