218816 has 28 divisors (see below), whose sum is σ = 469392. Its totient is φ = 100608.

The previous prime is 218809. The next prime is 218819. The reversal of 218816 is 618812.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (218819) by changing a digit.

218816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 701 + ... + 963.

It is an arithmetic number, because the mean of its divisors is an integer number (16764).

2²¹⁸⁸¹⁶ is an apocalyptic number.

218816 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (234696).

218816 is an abundant number, since it is smaller than the sum of its proper divisors (250576).

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

218816 is a wasteful number, since it uses less digits than its factorization.

218816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 278 counting only the distinct ones).

The product of its digits is 768, while the sum is 26.

The square root of 218816 is about 467.7777249934. Note that the first 4 decimals coincide. The cubic root of 218816 is about 60.2596157813.

It can be divided in two parts, 21 and 8816, that multiplied together give a triangular number (185136 = T₆₀₈).

The spelling of 218816 in words is "two hundred eighteen thousand, eight hundred sixteen".