216522 has 24 divisors (see below), whose sum is σ = 490464. Its totient is φ = 68904.

The previous prime is 216509. The next prime is 216523. The reversal of 216522 is 225612.

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

It is a junction number, because it is equal to n+sod(n) for n = 216495 and 216504.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216522.

It is not an unprimeable number, because it can be changed into a prime (216523) by changing a digit.

216522 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 11 ways as a sum of consecutive naturals, for example, 153 + ... + 675.

It is an arithmetic number, because the mean of its divisors is an integer number (20436).

2²¹⁶⁵²² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216522, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (245232).

216522 is an abundant number, since it is smaller than the sum of its proper divisors (273942).

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

216522 is a wasteful number, since it uses less digits than its factorization.

216522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554 (or 551 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 216522 is about 465.3192452500. The cubic root of 216522 is about 60.0482944503.

It can be divided in two parts, 2165 and 22, that added together give a 7-th power (2187 = 3⁷).

The spelling of 216522 in words is "two hundred sixteen thousand, five hundred twenty-two".