18438816 has 96 divisors (see below), whose sum is σ = 55641600. Its totient is φ = 5287680.

The previous prime is 18438803. The next prime is 18438817. The reversal of 18438816 is 61883481.

It is a tau number, because it is divible by the number of its divisors (96).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (18438817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19605 + ... + 20523.

It is an arithmetic number, because the mean of its divisors is an integer number (579600).

Almost surely, 2^18438816 is an apocalyptic number.

18438816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18438816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27820800).

18438816 is an abundant number, since it is smaller than the sum of its proper divisors (37202784).

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

18438816 is a wasteful number, since it uses less digits than its factorization.

18438816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 962 (or 954 counting only the distinct ones).

The product of its digits is 36864, while the sum is 39.

The square root of 18438816 is about 4294.0442475596. The cubic root of 18438816 is about 264.1867365703.

It can be divided in two parts, 18 and 438816, that added together give a palindrome (438834).

The spelling of 18438816 in words is "eighteen million, four hundred thirty-eight thousand, eight hundred sixteen".