216864109 has 16 divisors (see below), whose sum is σ = 270729216. Its totient is φ = 168764400.

The previous prime is 216864103. The next prime is 216864149. The reversal of 216864109 is 901468612.

It is a happy number.

It is not a de Polignac number, because 216864109 - 2⁵ = 216864077 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 (216864103) 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, 82404 + ... + 84994.

It is an arithmetic number, because the mean of its divisors is an integer number (16920576).

Almost surely, 2^216864109 is an apocalyptic number.

It is an amenable number.

216864109 is a deficient number, since it is larger than the sum of its proper divisors (53865107).

216864109 is a wasteful number, since it uses less digits than its factorization.

216864109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3696.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 216864109 is about 14726.3066992373. The cubic root of 216864109 is about 600.7990363551.

The spelling of 216864109 in words is "two hundred sixteen million, eight hundred sixty-four thousand, one hundred nine".