16218644 has 12 divisors (see below), whose sum is σ = 30566004. Its totient is φ = 7485504.

The previous prime is 16218637. The next prime is 16218667. The reversal of 16218644 is 44681261.

It can be written as a sum of positive squares in 2 ways, for example, as 1488400 + 14730244 = 1220^2 + 3838^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 16218644.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155897 + ... + 156000.

It is an arithmetic number, because the mean of its divisors is an integer number (2547167).

Almost surely, 2^16218644 is an apocalyptic number.

It is an amenable number.

16218644 is a deficient number, since it is larger than the sum of its proper divisors (14347360).

16218644 is a wasteful number, since it uses less digits than its factorization.

16218644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311914 (or 311912 counting only the distinct ones).

The product of its digits is 9216, while the sum is 32.

The square root of 16218644 is about 4027.2377630331. The cubic root of 16218644 is about 253.1268300228.

The spelling of 16218644 in words is "sixteen million, two hundred eighteen thousand, six hundred forty-four".