216669 has 4 divisors (see below), whose sum is σ = 288896. Its totient is φ = 144444.

The previous prime is 216661. The next prime is 216679. The reversal of 216669 is 966612.

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 not a de Polignac number, because 216669 - 2³ = 216661 is a prime.

It is a super-2 number, since 2×216669² = 93890911122, which contains 22 as substring.

It is a D-number.

It is a Duffinian 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, 36109 + ... + 36114.

It is an arithmetic number, because the mean of its divisors is an integer number (72224).

2²¹⁶⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

216669 is a deficient number, since it is larger than the sum of its proper divisors (72227).

216669 is an equidigital number, since it uses as much as digits as its factorization.

216669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72226.

The product of its digits is 3888, while the sum is 30.

The square root of 216669 is about 465.4771745209. The cubic root of 216669 is about 60.0618806024.

The spelling of 216669 in words is "two hundred sixteen thousand, six hundred sixty-nine".