256316220053021 has 2 divisors, whose sum is σ = 256316220053022. Its totient is φ = 256316220053020.

The previous prime is 256316220052999. The next prime is 256316220053029. The reversal of 256316220053021 is 120350022613652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 156556675332121 + 99759544720900 = 12512261^2 + 9987970^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256316220053021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256316220053029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128158110026510 + 128158110026511.

It is an arithmetic number, because the mean of its divisors is an integer number (128158110026511).

Almost surely, 2^{256316220053021} is an apocalyptic number.

It is an amenable number.

256316220053021 is a deficient number, since it is larger than the sum of its proper divisors (1).

256316220053021 is an equidigital number, since it uses as much as digits as its factorization.

256316220053021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129600, while the sum is 38.

Adding to 256316220053021 its reverse (120350022613652), we get a palindrome (376666242666673).

The spelling of 256316220053021 in words is "two hundred fifty-six trillion, three hundred sixteen billion, two hundred twenty million, fifty-three thousand, twenty-one".