16218666 has 48 divisors (see below), whose sum is σ = 37814400. Its totient is φ = 5007744.

The previous prime is 16218637. The next prime is 16218667. The reversal of 16218666 is 66681261.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 16218666.

It is not an unprimeable number, because it can be changed into a prime (16218667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15570 + ... + 16578.

It is an arithmetic number, because the mean of its divisors is an integer number (787800).

Almost surely, 2^16218666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16218666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18907200).

16218666 is an abundant number, since it is smaller than the sum of its proper divisors (21595734).

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

16218666 is a wasteful number, since it uses less digits than its factorization.

16218666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1083 (or 1080 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 16218666 is about 4027.2404944329. The cubic root of 16218666 is about 253.1269444752.

The spelling of 16218666 in words is "sixteen million, two hundred eighteen thousand, six hundred sixty-six".