216660 has 48 divisors (see below), whose sum is σ = 637056. Its totient is φ = 54912.

The previous prime is 216653. The next prime is 216661. The reversal of 216660 is 66612.

216660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216660.

It is not an unprimeable number, because it can be changed into a prime (216661) by changing a digit.

216660 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1302 + ... + 1458.

It is an arithmetic number, because the mean of its divisors is an integer number (13272).

2²¹⁶⁶⁶⁰ is an apocalyptic number.

216660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (318528).

216660 is an abundant number, since it is smaller than the sum of its proper divisors (420396).

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

216660 is a wasteful number, since it uses less digits than its factorization.

216660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 216660 is about 465.4675069218. The cubic root of 216660 is about 60.0610489738.

The spelling of 216660 in words is "two hundred sixteen thousand, six hundred sixty".