18384220 has 24 divisors (see below), whose sum is σ = 39506544.
Its totient is φ = 7182336.
The previous prime is 18384211. The next prime is 18384221. The reversal of 18384220 is 2248381.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (18384221) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9829 + ... + 11548.
It is an arithmetic number, because the mean of its divisors is an integer number (1646106).
Almost surely, 218384220 is an apocalyptic number.
18384220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.
It is an amenable number.
18384220 is an abundant number, since it is smaller than the sum of its proper divisors (21122324).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
18384220 is a wasteful number, since it uses less digits than its factorization.
18384220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 21429 (or 21427 counting only the distinct ones).
The product of its (nonzero) digits is 3072, while the sum is 28.
The square root of 18384220 is about 4287.6823576380.
The cubic root of 18384220 is about 263.9257328591.
The spelling of 18384220 in words is "eighteen million, three hundred eighty-four thousand, two hundred twenty".