856663897 has 2 divisors, whose sum is σ = 856663898. Its totient is φ = 856663896.

The previous prime is 856663883. The next prime is 856663901. The reversal of 856663897 is 798366658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 668946496 + 187717401 = 25864^2 + 13701^2 .

It is a cyclic number.

It is not a de Polignac number, because 856663897 - 2¹¹ = 856661849 is a prime.

It is not a weakly prime, because it can be changed into another prime (856663817) 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, 428331948 + 428331949.

It is an arithmetic number, because the mean of its divisors is an integer number (428331949).

Almost surely, 2^856663897 is an apocalyptic number.

It is an amenable number.

856663897 is a deficient number, since it is larger than the sum of its proper divisors (1).

856663897 is an equidigital number, since it uses as much as digits as its factorization.

856663897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13063680, while the sum is 58.

The square root of 856663897 is about 29268.8212437741. The cubic root of 856663897 is about 949.7372854346.

The spelling of 856663897 in words is "eight hundred fifty-six million, six hundred sixty-three thousand, eight hundred ninety-seven".