216385809 has 8 divisors (see below), whose sum is σ = 305485920. Its totient is φ = 135771456.

The previous prime is 216385787. The next prime is 216385853. The reversal of 216385809 is 908583612.

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

It is not a de Polignac number, because 216385809 - 2⁸ = 216385553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216385409) 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 in 7 ways as a sum of consecutive naturals, for example, 2121379 + ... + 2121480.

It is an arithmetic number, because the mean of its divisors is an integer number (38185740).

Almost surely, 2^216385809 is an apocalyptic number.

It is an amenable number.

216385809 is a deficient number, since it is larger than the sum of its proper divisors (89100111).

216385809 is a wasteful number, since it uses less digits than its factorization.

216385809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4242879.

The product of its (nonzero) digits is 103680, while the sum is 42.

The square root of 216385809 is about 14710.0580896202. The cubic root of 216385809 is about 600.3570180769.

The spelling of 216385809 in words is "two hundred sixteen million, three hundred eighty-five thousand, eight hundred nine".