216804 has 48 divisors (see below), whose sum is σ = 604800. Its totient is φ = 59136.

The previous prime is 216803. The next prime is 216829. The reversal of 216804 is 408612.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (216803) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2392 + ... + 2480.

It is an arithmetic number, because the mean of its divisors is an integer number (12600).

2²¹⁶⁸⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (302400).

216804 is an abundant number, since it is smaller than the sum of its proper divisors (387996).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216804 is a wasteful number, since it uses less digits than its factorization.

216804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 216804 is about 465.6221644209. The cubic root of 216804 is about 60.0743522687.

It can be divided in two parts, 21 and 6804, that multiplied together give a square (142884 = 378²).

The spelling of 216804 in words is "two hundred sixteen thousand, eight hundred four".