856989657 has 6 divisors (see below), whose sum is σ = 1237873962. Its totient is φ = 571326432.

The previous prime is 856989649. The next prime is 856989689. The reversal of 856989657 is 756989658.

856989657 is a `hidden beast` number, since 8 + 569 + 8 + 9 + 65 + 7 = 666.

It can be written as a sum of positive squares in only one way, i.e., 660541401 + 196448256 = 25701^2 + 14016^2 .

It is not a de Polignac number, because 856989657 - 2³ = 856989649 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 856989594 and 856989603.

It is not an unprimeable number, because it can be changed into a prime (856989607) 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 in 5 ways as a sum of consecutive naturals, for example, 47610528 + ... + 47610545.

It is an arithmetic number, because the mean of its divisors is an integer number (206312327).

Almost surely, 2^856989657 is an apocalyptic number.

It is an amenable number.

856989657 is a deficient number, since it is larger than the sum of its proper divisors (380884305).

856989657 is a wasteful number, since it uses less digits than its factorization.

856989657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95221079 (or 95221076 counting only the distinct ones).

The product of its digits is 32659200, while the sum is 63.

The square root of 856989657 is about 29274.3856810011. The cubic root of 856989657 is about 949.8576543880.

Subtracting from 856989657 its reverse (756989658), we obtain a palindrome (99999999).

The spelling of 856989657 in words is "eight hundred fifty-six million, nine hundred eighty-nine thousand, six hundred fifty-seven".