856008757721 has 8 divisors (see below), whose sum is σ = 922286993544. Its totient is φ = 789792151680.

The previous prime is 856008757697. The next prime is 856008757727. The reversal of 856008757721 is 127757800658.

It can be written as a sum of positive squares in 4 ways, for example, as 147026233600 + 708982524121 = 383440^2 + 842011^2 .

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 856008757721 - 2¹⁰ = 856008756697 is a prime.

It is a super-2 number, since 2×856008757721² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856008757727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15378590 + ... + 15434151.

It is an arithmetic number, because the mean of its divisors is an integer number (115285874193).

Almost surely, 2^856008757721 is an apocalyptic number.

It is an amenable number.

856008757721 is a deficient number, since it is larger than the sum of its proper divisors (66278235823).

856008757721 is a wasteful number, since it uses less digits than its factorization.

856008757721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30814891.

The product of its (nonzero) digits is 6585600, while the sum is 56.

The spelling of 856008757721 in words is "eight hundred fifty-six billion, eight million, seven hundred fifty-seven thousand, seven hundred twenty-one".