216611 has 8 divisors (see below), whose sum is σ = 227664. Its totient is φ = 205920.

The previous prime is 216607. The next prime is 216617. The reversal of 216611 is 116612.

It is a happy number.

216611 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 cyclic number.

It is not a de Polignac number, because 216611 - 2² = 216607 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216611.

It is not an unprimeable number, because it can be changed into a prime (216617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3200 + ... + 3266.

It is an arithmetic number, because the mean of its divisors is an integer number (28458).

2²¹⁶⁶¹¹ is an apocalyptic number.

216611 is a deficient number, since it is larger than the sum of its proper divisors (11053).

216611 is an equidigital number, since it uses as much as digits as its factorization.

216611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181.

The product of its digits is 72, while the sum is 17.

The square root of 216611 is about 465.4148686924. The cubic root of 216611 is about 60.0565208140.

Subtracting from 216611 its reverse (116612), we obtain a palindrome (99999).

It can be divided in two parts, 21 and 6611, that multiplied together give a palindrome (138831).

The spelling of 216611 in words is "two hundred sixteen thousand, six hundred eleven".