18209984 has 56 divisors (see below), whose sum is σ = 39898320. Its totient is φ = 8193024.

The previous prime is 18209981. The next prime is 18209987. The reversal of 18209984 is 48990281.

It is an interprime number because it is at equal distance from previous prime (18209981) and next prime (18209987).

It is not an unprimeable number, because it can be changed into a prime (18209981) 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 7 ways as a sum of consecutive naturals, for example, 35522 + ... + 36030.

It is an arithmetic number, because the mean of its divisors is an integer number (712470).

Almost surely, 2^18209984 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 18209984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19949160).

18209984 is an abundant number, since it is smaller than the sum of its proper divisors (21688336).

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

18209984 is a wasteful number, since it uses less digits than its factorization.

18209984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 577 (or 567 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 18209984 is about 4267.3157839560. The cubic root of 18209984 is about 263.0893016004.

The spelling of 18209984 in words is "eighteen million, two hundred nine thousand, nine hundred eighty-four".