216663 has 4 divisors (see below), whose sum is σ = 288888. Its totient is φ = 144440.

The previous prime is 216661. The next prime is 216679. The reversal of 216663 is 366612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 216663 - 2¹ = 216661 is a prime.

It is a D-number.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36108 + ... + 36113.

It is an arithmetic number, because the mean of its divisors is an integer number (72222).

2²¹⁶⁶⁶³ is an apocalyptic number.

216663 is a deficient number, since it is larger than the sum of its proper divisors (72225).

216663 is an equidigital number, since it uses as much as digits as its factorization.

216663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72224.

The product of its digits is 1296, while the sum is 24.

The square root of 216663 is about 465.4707294772. The cubic root of 216663 is about 60.0613261858.

The spelling of 216663 in words is "two hundred sixteen thousand, six hundred sixty-three".