856327721 has 2 divisors, whose sum is σ = 856327722. Its totient is φ = 856327720.

The previous prime is 856327669. The next prime is 856327727. The reversal of 856327721 is 127723658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 537312400 + 319015321 = 23180^2 + 17861^2 .

It is a cyclic number.

It is not a de Polignac number, because 856327721 - 2⁶ = 856327657 is a prime.

It is a super-3 number, since 3×856327721³ (a number of 28 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (856327727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428163860 + 428163861.

It is an arithmetic number, because the mean of its divisors is an integer number (428163861).

Almost surely, 2^856327721 is an apocalyptic number.

It is an amenable number.

856327721 is a deficient number, since it is larger than the sum of its proper divisors (1).

856327721 is an equidigital number, since it uses as much as digits as its factorization.

856327721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 141120, while the sum is 41.

The square root of 856327721 is about 29263.0777772947. The cubic root of 856327721 is about 949.6130357507.

The spelling of 856327721 in words is "eight hundred fifty-six million, three hundred twenty-seven thousand, seven hundred twenty-one".