216784 has 20 divisors (see below), whose sum is σ = 445284. Its totient is φ = 101888.

The previous prime is 216781. The next prime is 216787. The reversal of 216784 is 487612.

216784 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (216781) and next prime (216787).

It can be written as a sum of positive squares in 2 ways, for example, as 138384 + 78400 = 372^2 + 280^2 .

It is a plaindrome in base 13.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127 + ... + 670.

2²¹⁶⁷⁸⁴ is an apocalyptic number.

It is an amenable number.

216784 is an abundant number, since it is smaller than the sum of its proper divisors (228500).

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

216784 is a wasteful number, since it uses less digits than its factorization.

216784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 822 (or 816 counting only the distinct ones).

The product of its digits is 2688, while the sum is 28.

The square root of 216784 is about 465.6006872847. The cubic root of 216784 is about 60.0725049412.

It can be divided in two parts, 216 and 784, that added together give a cube (1000 = 10³).

The spelling of 216784 in words is "two hundred sixteen thousand, seven hundred eighty-four".