256842857 has 4 divisors (see below), whose sum is σ = 258187776. Its totient is φ = 255497940.

The previous prime is 256842853. The next prime is 256842877. The reversal of 256842857 is 758248652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256842857 - 2² = 256842853 is a prime.

It is a super-3 number, since 3×256842857³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256842853) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 672173 + ... + 672554.

It is an arithmetic number, because the mean of its divisors is an integer number (64546944).

Almost surely, 2^256842857 is an apocalyptic number.

It is an amenable number.

256842857 is a deficient number, since it is larger than the sum of its proper divisors (1344919).

256842857 is a wasteful number, since it uses less digits than its factorization.

256842857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1344918.

The product of its digits is 1075200, while the sum is 47.

The square root of 256842857 is about 16026.3176369371. The cubic root of 256842857 is about 635.6565074571.

The spelling of 256842857 in words is "two hundred fifty-six million, eight hundred forty-two thousand, eight hundred fifty-seven".