856207129 has 2 divisors, whose sum is σ = 856207130. Its totient is φ = 856207128.

The previous prime is 856207117. The next prime is 856207139. The reversal of 856207129 is 921702658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 657819904 + 198387225 = 25648^2 + 14085^2 .

It is a cyclic number.

It is not a de Polignac number, because 856207129 - 2¹⁷ = 856076057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 856207091 and 856207100.

It is not a weakly prime, because it can be changed into another prime (856207109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428103564 + 428103565.

It is an arithmetic number, because the mean of its divisors is an integer number (428103565).

Almost surely, 2^856207129 is an apocalyptic number.

It is an amenable number.

856207129 is a deficient number, since it is larger than the sum of its proper divisors (1).

856207129 is an equidigital number, since it uses as much as digits as its factorization.

856207129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 856207129 is about 29261.0172242866. The cubic root of 856207129 is about 949.5684573694.

The spelling of 856207129 in words is "eight hundred fifty-six million, two hundred seven thousand, one hundred twenty-nine".