256312321 has 2 divisors, whose sum is σ = 256312322. Its totient is φ = 256312320.

The previous prime is 256312313. The next prime is 256312327. The reversal of 256312321 is 123213652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 253956096 + 2356225 = 15936^2 + 1535^2 .

It is a cyclic number.

It is not a de Polignac number, because 256312321 - 2³ = 256312313 is a prime.

It is not a weakly prime, because it can be changed into another prime (256312327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128156160 + 128156161.

It is an arithmetic number, because the mean of its divisors is an integer number (128156161).

Almost surely, 2^256312321 is an apocalyptic number.

It is an amenable number.

256312321 is a deficient number, since it is larger than the sum of its proper divisors (1).

256312321 is an equidigital number, since it uses as much as digits as its factorization.

256312321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 25.

The square root of 256312321 is about 16009.7570562454. The cubic root of 256312321 is about 635.2185339139.

Adding to 256312321 its reverse (123213652), we get a palindrome (379525973).

It can be divided in two parts, 2563 and 12321, that added together give a square (14884 = 122²).

The spelling of 256312321 in words is "two hundred fifty-six million, three hundred twelve thousand, three hundred twenty-one".