18216444 has 24 divisors (see below), whose sum is σ = 42618240. Its totient is φ = 6055984.

The previous prime is 18216433. The next prime is 18216449. The reversal of 18216444 is 44461281.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18216449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3217 + ... + 6839.

It is an arithmetic number, because the mean of its divisors is an integer number (1775760).

Almost surely, 2^18216444 is an apocalyptic number.

It is an amenable number.

18216444 is an abundant number, since it is smaller than the sum of its proper divisors (24401796).

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

18216444 is a wasteful number, since it uses less digits than its factorization.

18216444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4049 (or 4047 counting only the distinct ones).

The product of its digits is 6144, while the sum is 30.

The square root of 18216444 is about 4268.0726329340. The cubic root of 18216444 is about 263.1204082716.

The spelling of 18216444 in words is "eighteen million, two hundred sixteen thousand, four hundred forty-four".