256865281 has 8 divisors (see below), whose sum is σ = 258585728. Its totient is φ = 255150000.

The previous prime is 256865269. The next prime is 256865299. The reversal of 256865281 is 182568652.

256865281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 6-Lehmer number, since φ(256865281) divides (256865281-1)⁶.

It is a cyclic number.

It is not a de Polignac number, because 256865281 - 2⁵ = 256865249 is a prime.

It is a super-2 number, since 2×256865281² = 131959545166417922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256865251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 157651 + ... + 159271.

It is an arithmetic number, because the mean of its divisors is an integer number (32323216).

Almost surely, 2^256865281 is an apocalyptic number.

256865281 is the 7168-th centered decagonal number.

It is an amenable number.

256865281 is a deficient number, since it is larger than the sum of its proper divisors (1720447).

256865281 is a wasteful number, since it uses less digits than its factorization.

256865281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2583.

The product of its digits is 230400, while the sum is 43.

The square root of 256865281 is about 16027.0172209304. The cubic root of 256865281 is about 635.6750058584.

The spelling of 256865281 in words is "two hundred fifty-six million, eight hundred sixty-five thousand, two hundred eighty-one".