216138939 has 8 divisors (see below), whose sum is σ = 288360720. Its totient is φ = 144004896.

The previous prime is 216138919. The next prime is 216138961. The reversal of 216138939 is 939831612.

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

It is not a de Polignac number, because 216138939 - 2⁵ = 216138907 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216138939.

It is not an unprimeable number, because it can be changed into a prime (216138919) 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, 15952 + ... + 26205.

It is an arithmetic number, because the mean of its divisors is an integer number (36045090).

Almost surely, 2^216138939 is an apocalyptic number.

216138939 is a deficient number, since it is larger than the sum of its proper divisors (72221781).

216138939 is a wasteful number, since it uses less digits than its factorization.

216138939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43869.

The product of its digits is 69984, while the sum is 42.

The square root of 216138939 is about 14701.6644976003. The cubic root of 216138939 is about 600.1286196486.

The spelling of 216138939 in words is "two hundred sixteen million, one hundred thirty-eight thousand, nine hundred thirty-nine".