18409518 has 40 divisors (see below), whose sum is σ = 43429320. Its totient is φ = 5812560.

The previous prime is 18409513. The next prime is 18409529. The reversal of 18409518 is 81590481.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18409513) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 88 + ... + 6068.

It is an arithmetic number, because the mean of its divisors is an integer number (1085733).

Almost surely, 2^18409518 is an apocalyptic number.

18409518 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 18409518, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21714660).

18409518 is an abundant number, since it is smaller than the sum of its proper divisors (25019802).

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

18409518 is a wasteful number, since it uses less digits than its factorization.

18409518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6014 (or 6005 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 18409518 is about 4290.6314220637. The cubic root of 18409518 is about 264.0467375930.

Adding to 18409518 its reverse (81590481), we get a palindrome (99999999).

The spelling of 18409518 in words is "eighteen million, four hundred nine thousand, five hundred eighteen".