856804889 has 2 divisors, whose sum is σ = 856804890. Its totient is φ = 856804888.

The previous prime is 856804859. The next prime is 856804891. The reversal of 856804889 is 988408658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 828979264 + 27825625 = 28792^2 + 5275^2 .

It is a cyclic number.

It is not a de Polignac number, because 856804889 - 2⁸ = 856804633 is a prime.

It is a super-2 number, since 2×856804889² = 1468229235628604642, which contains 22 as substring.

Together with 856804891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (856804859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428402444 + 428402445.

It is an arithmetic number, because the mean of its divisors is an integer number (428402445).

Almost surely, 2^856804889 is an apocalyptic number.

It is an amenable number.

856804889 is a deficient number, since it is larger than the sum of its proper divisors (1).

856804889 is an equidigital number, since it uses as much as digits as its factorization.

856804889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4423680, while the sum is 56.

The square root of 856804889 is about 29271.2297145166. The cubic root of 856804889 is about 949.7893859975.

The spelling of 856804889 in words is "eight hundred fifty-six million, eight hundred four thousand, eight hundred eighty-nine".