16218216 has 72 divisors (see below), whose sum is σ = 51106770. Its totient is φ = 4632768.

The previous prime is 16218211. The next prime is 16218217. The reversal of 16218216 is 61281261.

It can be written as a sum of positive squares in only one way, i.e., 15920100 + 298116 = 3990^2 + 546^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 16218216.

It is not an unprimeable number, because it can be changed into a prime (16218211) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1230 + ... + 5826.

Almost surely, 2^16218216 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 16218216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25553385).

16218216 is an abundant number, since it is smaller than the sum of its proper divisors (34888554).

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

16218216 is a wasteful number, since it uses less digits than its factorization.

16218216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4623 (or 4609 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 16218216 is about 4027.1846245237. The cubic root of 16218216 is about 253.1246033830.

Adding to 16218216 its reverse (61281261), we get a palindrome (77499477).

The spelling of 16218216 in words is "sixteen million, two hundred eighteen thousand, two hundred sixteen".