315820217 has 2 divisors, whose sum is σ = 315820218. Its totient is φ = 315820216.

The previous prime is 315820207. The next prime is 315820231. The reversal of 315820217 is 712028513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 311028496 + 4791721 = 17636^2 + 2189^2 .

It is a cyclic number.

It is not a de Polignac number, because 315820217 - 2⁴ = 315820201 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 315820217.

It is not a weakly prime, because it can be changed into another prime (315820207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157910108 + 157910109.

It is an arithmetic number, because the mean of its divisors is an integer number (157910109).

Almost surely, 2^315820217 is an apocalyptic number.

It is an amenable number.

315820217 is a deficient number, since it is larger than the sum of its proper divisors (1).

315820217 is an equidigital number, since it uses as much as digits as its factorization.

315820217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 315820217 is about 17771.3313232296. The cubic root of 315820217 is about 680.9992639879. Note that the first 3 decimals are identical.

The spelling of 315820217 in words is "three hundred fifteen million, eight hundred twenty thousand, two hundred seventeen".