216688 has 20 divisors (see below), whose sum is σ = 435240. Its totient is φ = 104384.

The previous prime is 216679. The next prime is 216703. The reversal of 216688 is 886612.

216688 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231 + ... + 697.

It is an arithmetic number, because the mean of its divisors is an integer number (21762).

2²¹⁶⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217620).

216688 is an abundant number, since it is smaller than the sum of its proper divisors (218552).

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

216688 is a wasteful number, since it uses less digits than its factorization.

216688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504 (or 498 counting only the distinct ones).

The product of its digits is 4608, while the sum is 31.

The square root of 216688 is about 465.4975832376. The cubic root of 216688 is about 60.0636361871.

The spelling of 216688 in words is "two hundred sixteen thousand, six hundred eighty-eight".