216138184 has 8 divisors (see below), whose sum is σ = 405259110. Its totient is φ = 108069088.

The previous prime is 216138179. The next prime is 216138203. The reversal of 216138184 is 481831612.

It can be written as a sum of positive squares in only one way, i.e., 111894084 + 104244100 = 10578^2 + 10210^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13508629 + ... + 13508644.

Almost surely, 2^216138184 is an apocalyptic number.

It is an amenable number.

216138184 is a deficient number, since it is larger than the sum of its proper divisors (189120926).

216138184 is a wasteful number, since it uses less digits than its factorization.

216138184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27017279 (or 27017275 counting only the distinct ones).

The product of its digits is 9216, while the sum is 34.

The square root of 216138184 is about 14701.6388202132. The cubic root of 216138184 is about 600.1279208733.

Adding to 216138184 its reverse (481831612), we get a palindrome (697969796).

The spelling of 216138184 in words is "two hundred sixteen million, one hundred thirty-eight thousand, one hundred eighty-four".