216646 has 8 divisors (see below), whose sum is σ = 327600. Its totient is φ = 107448.

The previous prime is 216641. The next prime is 216647. The reversal of 216646 is 646612.

It is a happy number.

216646 is nontrivially palindromic in base 12.

216646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a self number, because there is not a number n which added to its sum of digits gives 216646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216641) by changing a digit.

216646 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 3 ways as a sum of consecutive naturals, for example, 66 + ... + 661.

It is an arithmetic number, because the mean of its divisors is an integer number (40950).

2²¹⁶⁶⁴⁶ is an apocalyptic number.

216646 is a deficient number, since it is larger than the sum of its proper divisors (110954).

216646 is a wasteful number, since it uses less digits than its factorization.

216646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878.

The product of its digits is 1728, while the sum is 25.

The square root of 216646 is about 465.4524680351. The cubic root of 216646 is about 60.0597552835.

The spelling of 216646 in words is "two hundred sixteen thousand, six hundred forty-six".