18438885 has 12 divisors (see below), whose sum is σ = 31960812. Its totient is φ = 9834048.

The previous prime is 18438883. The next prime is 18438907. The reversal of 18438885 is 58883481.

It can be written as a sum of positive squares in 2 ways, for example, as 7667361 + 10771524 = 2769^2 + 3282^2 .

It is not a de Polignac number, because 18438885 - 2¹ = 18438883 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 409753 = 18438885 / (1 + 8 + 4 + 3 + 8 + 8 + 8 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 18438885.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18438881) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 204832 + ... + 204921.

It is an arithmetic number, because the mean of its divisors is an integer number (2663401).

Almost surely, 2^18438885 is an apocalyptic number.

18438885 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18438885 is a deficient number, since it is larger than the sum of its proper divisors (13521927).

18438885 is a wasteful number, since it uses less digits than its factorization.

18438885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409764 (or 409761 counting only the distinct ones).

The product of its digits is 245760, while the sum is 45.

The square root of 18438885 is about 4294.0522819360. The cubic root of 18438885 is about 264.1870661081.

The spelling of 18438885 in words is "eighteen million, four hundred thirty-eight thousand, eight hundred eighty-five".