856964909 has 2 divisors, whose sum is σ = 856964910. Its totient is φ = 856964908.

The previous prime is 856964893. The next prime is 856964921. The reversal of 856964909 is 909469658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 844076809 + 12888100 = 29053^2 + 3590^2 .

It is a cyclic number.

It is not a de Polignac number, because 856964909 - 2⁴ = 856964893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856964939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428482454 + 428482455.

It is an arithmetic number, because the mean of its divisors is an integer number (428482455).

Almost surely, 2^856964909 is an apocalyptic number.

It is an amenable number.

856964909 is a deficient number, since it is larger than the sum of its proper divisors (1).

856964909 is an equidigital number, since it uses as much as digits as its factorization.

856964909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4199040, while the sum is 56.

The square root of 856964909 is about 29273.9629876107. The cubic root of 856964909 is about 949.8485110246.

The spelling of 856964909 in words is "eight hundred fifty-six million, nine hundred sixty-four thousand, nine hundred nine".