216308209 has 16 divisors (see below), whose sum is σ = 236884032. Its totient is φ = 196319808.

The previous prime is 216308207. The next prime is 216308231. The reversal of 216308209 is 902803612.

It is a cyclic number.

It is not a de Polignac number, because 216308209 - 2¹ = 216308207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216308201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 330927 + ... + 331579.

It is an arithmetic number, because the mean of its divisors is an integer number (14805252).

Almost surely, 2^216308209 is an apocalyptic number.

It is an amenable number.

216308209 is a deficient number, since it is larger than the sum of its proper divisors (20575823).

216308209 is a wasteful number, since it uses less digits than its factorization.

216308209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1056.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 216308209 is about 14707.4202020613. The cubic root of 216308209 is about 600.2852430762.

The spelling of 216308209 in words is "two hundred sixteen million, three hundred eight thousand, two hundred nine".