256585321 has 2 divisors, whose sum is σ = 256585322. Its totient is φ = 256585320.

The previous prime is 256585297. The next prime is 256585363. The reversal of 256585321 is 123585652.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152769600 + 103815721 = 12360^2 + 10189^2 .

It is a cyclic number.

It is not a de Polignac number, because 256585321 - 2¹¹ = 256583273 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256085321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128292660 + 128292661.

It is an arithmetic number, because the mean of its divisors is an integer number (128292661).

Almost surely, 2^256585321 is an apocalyptic number.

It is an amenable number.

256585321 is a deficient number, since it is larger than the sum of its proper divisors (1).

256585321 is an equidigital number, since it uses as much as digits as its factorization.

256585321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72000, while the sum is 37.

The square root of 256585321 is about 16018.2808378427. The cubic root of 256585321 is about 635.4439790884.

The spelling of 256585321 in words is "two hundred fifty-six million, five hundred eighty-five thousand, three hundred twenty-one".