856642987609 has 8 divisors (see below), whose sum is σ = 909053879400. Its totient is φ = 804456554496.

The previous prime is 856642987579. The next prime is 856642987621. The reversal of 856642987609 is 906789246658.

It can be written as a sum of positive squares in 4 ways, for example, as 451084170384 + 405558817225 = 671628^2 + 636835^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 856642987609 - 2⁷ = 856642987481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856642987649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56106804 + ... + 56122069.

It is an arithmetic number, because the mean of its divisors is an integer number (113631734925).

Almost surely, 2^856642987609 is an apocalyptic number.

It is an amenable number.

856642987609 is a deficient number, since it is larger than the sum of its proper divisors (52410891791).

856642987609 is a wasteful number, since it uses less digits than its factorization.

856642987609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112229339.

The product of its (nonzero) digits is 313528320, while the sum is 70.

The spelling of 856642987609 in words is "eight hundred fifty-six billion, six hundred forty-two million, nine hundred eighty-seven thousand, six hundred nine".