216723 has 8 divisors (see below), whose sum is σ = 311248. Its totient is φ = 133344.

The previous prime is 216719. The next prime is 216731. The reversal of 216723 is 327612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 216723 - 2² = 216719 is a prime.

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

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a zygodrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 216723.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216703) 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, 2740 + ... + 2817.

It is an arithmetic number, because the mean of its divisors is an integer number (38906).

2²¹⁶⁷²³ is an apocalyptic number.

216723 is a deficient number, since it is larger than the sum of its proper divisors (94525).

216723 is a wasteful number, since it uses less digits than its factorization.

216723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5573.

The product of its digits is 504, while the sum is 21.

The square root of 216723 is about 465.5351758997. The cubic root of 216723 is about 60.0668698904.

Subtracting 216723 from its reverse (327612), we obtain a square (110889 = 333²).

It can be divided in two parts, 216 and 723, that added together give a palindrome (939).

The spelling of 216723 in words is "two hundred sixteen thousand, seven hundred twenty-three".