18409338 has 48 divisors (see below), whose sum is σ = 42456960. Its totient is φ = 5752032.

The previous prime is 18409333. The next prime is 18409367. The reversal of 18409338 is 83390481.

It is not an unprimeable number, because it can be changed into a prime (18409333) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21523 + ... + 22361.

It is an arithmetic number, because the mean of its divisors is an integer number (884520).

Almost surely, 2^18409338 is an apocalyptic number.

18409338 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 18409338, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21228480).

18409338 is an abundant number, since it is smaller than the sum of its proper divisors (24047622).

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

18409338 is a wasteful number, since it uses less digits than its factorization.

18409338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 923 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 18409338 is about 4290.6104460787. The cubic root of 18409338 is about 264.0458770134.

The spelling of 18409338 in words is "eighteen million, four hundred nine thousand, three hundred thirty-eight".