256321281 has 8 divisors (see below), whose sum is σ = 344371104. Its totient is φ = 169576160.

The previous prime is 256321277. The next prime is 256321283. The reversal of 256321281 is 182123652.

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

It is a cyclic number.

It is not a de Polignac number, because 256321281 - 2² = 256321277 is a prime.

It is a super-5 number, since 5×256321281⁵ (a number of 43 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (256321283) 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 7 ways as a sum of consecutive naturals, for example, 325716 + ... + 326501.

It is an arithmetic number, because the mean of its divisors is an integer number (43046388).

Almost surely, 2^256321281 is an apocalyptic number.

It is an amenable number.

256321281 is a deficient number, since it is larger than the sum of its proper divisors (88049823).

256321281 is a wasteful number, since it uses less digits than its factorization.

256321281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652351.

The product of its digits is 5760, while the sum is 30.

The square root of 256321281 is about 16010.0368831555. The cubic root of 256321281 is about 635.2259356803.

The spelling of 256321281 in words is "two hundred fifty-six million, three hundred twenty-one thousand, two hundred eighty-one".