856215317 has 2 divisors, whose sum is σ = 856215318. Its totient is φ = 856215316.

The previous prime is 856215287. The next prime is 856215361. The reversal of 856215317 is 713512658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 820765201 + 35450116 = 28649^2 + 5954^2 .

It is a cyclic number.

It is not a de Polignac number, because 856215317 - 2⁶ = 856215253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856215377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428107658 + 428107659.

It is an arithmetic number, because the mean of its divisors is an integer number (428107659).

Almost surely, 2^856215317 is an apocalyptic number.

It is an amenable number.

856215317 is a deficient number, since it is larger than the sum of its proper divisors (1).

856215317 is an equidigital number, since it uses as much as digits as its factorization.

856215317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 50400, while the sum is 38.

The square root of 856215317 is about 29261.1571370648. The cubic root of 856215317 is about 949.5714843012.

The spelling of 856215317 in words is "eight hundred fifty-six million, two hundred fifteen thousand, three hundred seventeen".