210816 has 64 divisors (see below), whose sum is σ = 632400. Its totient is φ = 69120.

The previous prime is 210811. The next prime is 210823. The reversal of 210816 is 618012.

Added to its reverse (618012) it gives a triangular number (828828 = T₁₂₈₇).

210816 is nontrivially palindromic in base 11.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 (210811) 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, 3426 + ... + 3486.

2²¹⁰⁸¹⁶ 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 210816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316200).

210816 is an abundant number, since it is smaller than the sum of its proper divisors (421584).

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

210816 is an equidigital number, since it uses as much as digits as its factorization.

210816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 66 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 210816 is about 459.1470352730. The cubic root of 210816 is about 59.5161079661.

Adding to 210816 its reverse (618012), we get a palindrome (828828).

The spelling of 210816 in words is "two hundred ten thousand, eight hundred sixteen".