216665329 has 2 divisors, whose sum is σ = 216665330. Its totient is φ = 216665328.

The previous prime is 216665297. The next prime is 216665333. The reversal of 216665329 is 923566612.

216665329 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157452304 + 59213025 = 12548^2 + 7695^2 .

It is a cyclic number.

It is not a de Polignac number, because 216665329 - 2⁵ = 216665297 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 216665291 and 216665300.

It is not a weakly prime, because it can be changed into another prime (216665369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108332664 + 108332665.

It is an arithmetic number, because the mean of its divisors is an integer number (108332665).

Almost surely, 2^216665329 is an apocalyptic number.

It is an amenable number.

216665329 is a deficient number, since it is larger than the sum of its proper divisors (1).

216665329 is an equidigital number, since it uses as much as digits as its factorization.

216665329 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 40.

The square root of 216665329 is about 14719.5560055322. The cubic root of 216665329 is about 600.6154139307.

The spelling of 216665329 in words is "two hundred sixteen million, six hundred sixty-five thousand, three hundred twenty-nine".