18421404 has 48 divisors (see below), whose sum is σ = 46172448. Its totient is φ = 5695488.

The previous prime is 18421399. The next prime is 18421411. The reversal of 18421404 is 40412481.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14274 + ... + 15510.

It is an arithmetic number, because the mean of its divisors is an integer number (961926).

Almost surely, 2^18421404 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 18421404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23086224).

18421404 is an abundant number, since it is smaller than the sum of its proper divisors (27751044).

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

18421404 is a wasteful number, since it uses less digits than its factorization.

18421404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1334 (or 1332 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 24.

The square root of 18421404 is about 4292.0163093819. The cubic root of 18421404 is about 264.1035521227.

Adding to 18421404 its reverse (40412481), we get a palindrome (58833885).

The spelling of 18421404 in words is "eighteen million, four hundred twenty-one thousand, four hundred four".