216209999 has 8 divisors (see below), whose sum is σ = 217437792. Its totient is φ = 214986240.

The previous prime is 216209989. The next prime is 216210031. The reversal of 216209999 is 999902612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216209999 - 2⁸ = 216209743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216209909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 208787 + ... + 209819.

It is an arithmetic number, because the mean of its divisors is an integer number (27179724).

Almost surely, 2^216209999 is an apocalyptic number.

216209999 is a deficient number, since it is larger than the sum of its proper divisors (1227793).

216209999 is a wasteful number, since it uses less digits than its factorization.

216209999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2017.

The product of its (nonzero) digits is 157464, while the sum is 47.

The square root of 216209999 is about 14704.0810321489. The cubic root of 216209999 is about 600.1943805387.

The spelling of 216209999 in words is "two hundred sixteen million, two hundred nine thousand, nine hundred ninety-nine".