856427849 has 2 divisors, whose sum is σ = 856427850. Its totient is φ = 856427848.

The previous prime is 856427807. The next prime is 856427851. The reversal of 856427849 is 948724658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 542890000 + 313537849 = 23300^2 + 17707^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-856427849 is a prime.

It is a Sophie Germain prime.

Together with 856427851, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 856427849.

It is not a weakly prime, because it can be changed into another prime (856427879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428213924 + 428213925.

It is an arithmetic number, because the mean of its divisors is an integer number (428213925).

Almost surely, 2^856427849 is an apocalyptic number.

It is an amenable number.

856427849 is a deficient number, since it is larger than the sum of its proper divisors (1).

856427849 is an equidigital number, since it uses as much as digits as its factorization.

856427849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3870720, while the sum is 53.

The square root of 856427849 is about 29264.7885521150. The cubic root of 856427849 is about 949.6500461717.

The spelling of 856427849 in words is "eight hundred fifty-six million, four hundred twenty-seven thousand, eight hundred forty-nine".