18444636 has 72 divisors (see below), whose sum is σ = 54329184. Its totient is φ = 5166720.

The previous prime is 18444623. The next prime is 18444661. The reversal of 18444636 is 63644481.

18444636 is a `hidden beast` number, since 18 + 4 + 4 + 4 + 636 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 18444636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12666 + ... + 14046.

It is an arithmetic number, because the mean of its divisors is an integer number (754572).

Almost surely, 2^18444636 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 18444636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27164592).

18444636 is an abundant number, since it is smaller than the sum of its proper divisors (35884548).

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

18444636 is a wasteful number, since it uses less digits than its factorization.

18444636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1451 (or 1446 counting only the distinct ones).

The product of its digits is 55296, while the sum is 36.

The square root of 18444636 is about 4294.7218769089. The cubic root of 18444636 is about 264.2145294804.

The spelling of 18444636 in words is "eighteen million, four hundred forty-four thousand, six hundred thirty-six".