856728239 has 2 divisors, whose sum is σ = 856728240. Its totient is φ = 856728238.

The previous prime is 856728193. The next prime is 856728269. The reversal of 856728239 is 932827658.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 856728239 - 2⁸ = 856727983 is a prime.

It is a super-2 number, since 2×856728239² = 1467966551000082242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856728269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428364119 + 428364120.

It is an arithmetic number, because the mean of its divisors is an integer number (428364120).

Almost surely, 2^856728239 is an apocalyptic number.

856728239 is a deficient number, since it is larger than the sum of its proper divisors (1).

856728239 is an equidigital number, since it uses as much as digits as its factorization.

856728239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 50.

The square root of 856728239 is about 29269.9203791196. The cubic root of 856728239 is about 949.7610623467.

The spelling of 856728239 in words is "eight hundred fifty-six million, seven hundred twenty-eight thousand, two hundred thirty-nine".