816510217 has 2 divisors, whose sum is σ = 816510218. Its totient is φ = 816510216.

The previous prime is 816510197. The next prime is 816510251. The reversal of 816510217 is 712015618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 442513296 + 373996921 = 21036^2 + 19339^2 .

It is a cyclic number.

It is not a de Polignac number, because 816510217 - 2¹⁵ = 816477449 is a prime.

It is not a weakly prime, because it can be changed into another prime (816510257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408255108 + 408255109.

It is an arithmetic number, because the mean of its divisors is an integer number (408255109).

Almost surely, 2^816510217 is an apocalyptic number.

It is an amenable number.

816510217 is a deficient number, since it is larger than the sum of its proper divisors (1).

816510217 is an equidigital number, since it uses as much as digits as its factorization.

816510217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 31.

The square root of 816510217 is about 28574.6429024056. The cubic root of 816510217 is about 934.6604682905.

The spelling of 816510217 in words is "eight hundred sixteen million, five hundred ten thousand, two hundred seventeen".