856408559 has 4 divisors (see below), whose sum is σ = 861140280. Its totient is φ = 851676840.

The previous prime is 856408543. The next prime is 856408561. The reversal of 856408559 is 955804658.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 955804658 = 2 ⋅477902329.

It is a cyclic number.

It is not a de Polignac number, because 856408559 - 2⁴ = 856408543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856408589) 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 3 ways as a sum of consecutive naturals, for example, 2365589 + ... + 2365950.

It is an arithmetic number, because the mean of its divisors is an integer number (215285070).

Almost surely, 2^856408559 is an apocalyptic number.

856408559 is a deficient number, since it is larger than the sum of its proper divisors (4731721).

856408559 is a wasteful number, since it uses less digits than its factorization.

856408559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4731720.

The product of its (nonzero) digits is 1728000, while the sum is 50.

The square root of 856408559 is about 29264.4589733007. The cubic root of 856408559 is about 949.6429162125.

The spelling of 856408559 in words is "eight hundred fifty-six million, four hundred eight thousand, five hundred fifty-nine".