856721567 has 8 divisors (see below), whose sum is σ = 954438240. Its totient is φ = 763549920.

The previous prime is 856721561. The next prime is 856721581. The reversal of 856721567 is 765127658.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-856721567 is a prime.

It is a super-3 number, since 3×856721567³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856721561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1135859 + ... + 1136612.

It is an arithmetic number, because the mean of its divisors is an integer number (119304780).

Almost surely, 2^856721567 is an apocalyptic number.

856721567 is a deficient number, since it is larger than the sum of its proper divisors (97716673).

856721567 is a wasteful number, since it uses less digits than its factorization.

856721567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2272513.

The product of its digits is 705600, while the sum is 47.

The square root of 856721567 is about 29269.8064052361. The cubic root of 856721567 is about 949.7585968343.

The spelling of 856721567 in words is "eight hundred fifty-six million, seven hundred twenty-one thousand, five hundred sixty-seven".