256105321 has 2 divisors, whose sum is σ = 256105322. Its totient is φ = 256105320.

The previous prime is 256105309. The next prime is 256105331. The reversal of 256105321 is 123501652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145540096 + 110565225 = 12064^2 + 10515^2 .

It is a cyclic number.

It is not a de Polignac number, because 256105321 - 2¹¹ = 256103273 is a prime.

It is not a weakly prime, because it can be changed into another prime (256105331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128052660 + 128052661.

It is an arithmetic number, because the mean of its divisors is an integer number (128052661).

Almost surely, 2^256105321 is an apocalyptic number.

It is an amenable number.

256105321 is a deficient number, since it is larger than the sum of its proper divisors (1).

256105321 is an equidigital number, since it uses as much as digits as its factorization.

256105321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 256105321 is about 16003.2909428030. The cubic root of 256105321 is about 635.0474852373.

Adding to 256105321 its reverse (123501652), we get a palindrome (379606973).

The spelling of 256105321 in words is "two hundred fifty-six million, one hundred five thousand, three hundred twenty-one".