18644418 has 72 divisors (see below), whose sum is σ = 45562608. Its totient is φ = 5711472.

The previous prime is 18644363. The next prime is 18644441. The reversal of 18644418 is 81444681.

18644418 is a `hidden beast` number, since 1 + 8 + 644 + 4 + 1 + 8 = 666.

It is a super-2 number, since 2×18644418² = 695228645117448, which contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 82021 + ... + 82247.

It is an arithmetic number, because the mean of its divisors is an integer number (632814).

Almost surely, 2^18644418 is an apocalyptic number.

18644418 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18644418, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22781304).

18644418 is an abundant number, since it is smaller than the sum of its proper divisors (26918190).

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

18644418 is a wasteful number, since it uses less digits than its factorization.

18644418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270 (or 245 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 18644418 is about 4317.9182484155. The cubic root of 18644418 is about 265.1650472966.

The spelling of 18644418 in words is "eighteen million, six hundred forty-four thousand, four hundred eighteen".