8211806857 has 2 divisors, whose sum is σ = 8211806858. Its totient is φ = 8211806856.

The previous prime is 8211806849. The next prime is 8211806861. The reversal of 8211806857 is 7586081128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7472565136 + 739241721 = 86444^2 + 27189^2 .

It is a cyclic number.

It is not a de Polignac number, because 8211806857 - 2³ = 8211806849 is a prime.

It is not a weakly prime, because it can be changed into another prime (8211806887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4105903428 + 4105903429.

It is an arithmetic number, because the mean of its divisors is an integer number (4105903429).

Almost surely, 2^8211806857 is an apocalyptic number.

It is an amenable number.

8211806857 is a deficient number, since it is larger than the sum of its proper divisors (1).

8211806857 is an equidigital number, since it uses as much as digits as its factorization.

8211806857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 215040, while the sum is 46.

The square root of 8211806857 is about 90619.0203930720. The cubic root of 8211806857 is about 2017.4970516201.

The spelling of 8211806857 in words is "eight billion, two hundred eleven million, eight hundred six thousand, eight hundred fifty-seven".