856539521 has 8 divisors (see below), whose sum is σ = 872528640. Its totient is φ = 840599568.

The previous prime is 856539511. The next prime is 856539539. The reversal of 856539521 is 125935658.

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 856539521 - 2¹⁴ = 856523137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856539511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23855 + ... + 47771.

It is an arithmetic number, because the mean of its divisors is an integer number (109066080).

Almost surely, 2^856539521 is an apocalyptic number.

It is an amenable number.

856539521 is a deficient number, since it is larger than the sum of its proper divisors (15989119).

856539521 is a wasteful number, since it uses less digits than its factorization.

856539521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24583.

The product of its digits is 324000, while the sum is 44.

The square root of 856539521 is about 29266.6964483523. The cubic root of 856539521 is about 949.6913202114.

The spelling of 856539521 in words is "eight hundred fifty-six million, five hundred thirty-nine thousand, five hundred twenty-one".