216943 has 4 divisors (see below), whose sum is σ = 220680. Its totient is φ = 213208.

The previous prime is 216919. The next prime is 216947. The reversal of 216943 is 349612.

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 216943 - 2⁵ = 216911 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1780 + ... + 1897.

It is an arithmetic number, because the mean of its divisors is an integer number (55170).

2²¹⁶⁹⁴³ is an apocalyptic number.

216943 is a deficient number, since it is larger than the sum of its proper divisors (3737).

216943 is an equidigital number, since it uses as much as digits as its factorization.

216943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3736.

The product of its digits is 1296, while the sum is 25.

The square root of 216943 is about 465.7714031582. The cubic root of 216943 is about 60.0871880575.

The spelling of 216943 in words is "two hundred sixteen thousand, nine hundred forty-three".