216689 has 4 divisors (see below), whose sum is σ = 236400. Its totient is φ = 196980.

The previous prime is 216679. The next prime is 216703. The reversal of 216689 is 986612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216689 - 2¹² = 212593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9839 + ... + 9860.

It is an arithmetic number, because the mean of its divisors is an integer number (59100).

2²¹⁶⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

216689 is a deficient number, since it is larger than the sum of its proper divisors (19711).

216689 is a wasteful number, since it uses less digits than its factorization.

216689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19710.

The product of its digits is 5184, while the sum is 32.

The square root of 216689 is about 465.4986573557. The cubic root of 216689 is about 60.0637285835.

The spelling of 216689 in words is "two hundred sixteen thousand, six hundred eighty-nine".