856649771 has 4 divisors (see below), whose sum is σ = 907040952. Its totient is φ = 806258592.

The previous prime is 856649711. The next prime is 856649791. The reversal of 856649771 is 177946658.

856649771 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 177946658 = 2 ⋅88973329.

It is not a de Polignac number, because 856649771 - 2¹⁰ = 856648747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856649711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25195565 + ... + 25195598.

It is an arithmetic number, because the mean of its divisors is an integer number (226760238).

Almost surely, 2^856649771 is an apocalyptic number.

856649771 is a deficient number, since it is larger than the sum of its proper divisors (50391181).

856649771 is a wasteful number, since it uses less digits than its factorization.

856649771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50391180.

The product of its digits is 2540160, while the sum is 53.

The square root of 856649771 is about 29268.5799279705. The cubic root of 856649771 is about 949.7320651599.

The spelling of 856649771 in words is "eight hundred fifty-six million, six hundred forty-nine thousand, seven hundred seventy-one".