216138 has 32 divisors (see below), whose sum is σ = 495936. Its totient is φ = 62208.

The previous prime is 216133. The next prime is 216149. The reversal of 216138 is 831612.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216138.

It is not an unprimeable number, because it can be changed into a prime (216133) 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, 1245 + ... + 1407.

It is an arithmetic number, because the mean of its divisors is an integer number (15498).

2²¹⁶¹³⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (247968).

216138 is an abundant number, since it is smaller than the sum of its proper divisors (279798).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216138 is a wasteful number, since it uses less digits than its factorization.

216138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198.

The product of its digits is 288, while the sum is 21.

The square root of 216138 is about 464.9064422010. The cubic root of 216138 is about 60.0127750575.

The spelling of 216138 in words is "two hundred sixteen thousand, one hundred thirty-eight".