8256768721 has 2 divisors, whose sum is σ = 8256768722. Its totient is φ = 8256768720.

The previous prime is 8256768701. The next prime is 8256768761. The reversal of 8256768721 is 1278676528.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5667078400 + 2589690321 = 75280^2 + 50889^2 .

It is a cyclic number.

It is not a de Polignac number, because 8256768721 - 2¹³ = 8256760529 is a prime.

It is not a weakly prime, because it can be changed into another prime (8256768701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4128384360 + 4128384361.

It is an arithmetic number, because the mean of its divisors is an integer number (4128384361).

Almost surely, 2^8256768721 is an apocalyptic number.

It is an amenable number.

8256768721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8256768721 is an equidigital number, since it uses as much as digits as its factorization.

8256768721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2257920, while the sum is 52.

The square root of 8256768721 is about 90866.7635662237. The cubic root of 8256768721 is about 2021.1724658408.

The spelling of 8256768721 in words is "eight billion, two hundred fifty-six million, seven hundred sixty-eight thousand, seven hundred twenty-one".