216078817 has 2 divisors, whose sum is σ = 216078818. Its totient is φ = 216078816.

The previous prime is 216078799. The next prime is 216078829. The reversal of 216078817 is 718870612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 169416256 + 46662561 = 13016^2 + 6831^2 .

It is a cyclic number.

It is not a de Polignac number, because 216078817 - 2¹¹ = 216076769 is a prime.

It is a super-2 number, since 2×216078817² = 93380110312238978, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 216078817.

It is not a weakly prime, because it can be changed into another prime (216078617) 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, 108039408 + 108039409.

It is an arithmetic number, because the mean of its divisors is an integer number (108039409).

Almost surely, 2^216078817 is an apocalyptic number.

It is an amenable number.

216078817 is a deficient number, since it is larger than the sum of its proper divisors (1).

216078817 is an equidigital number, since it uses as much as digits as its factorization.

216078817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37632, while the sum is 40.

The square root of 216078817 is about 14699.6196209290. The cubic root of 216078817 is about 600.0729698290.

The spelling of 216078817 in words is "two hundred sixteen million, seventy-eight thousand, eight hundred seventeen".