18309928 has 48 divisors (see below), whose sum is σ = 43020180. Its totient is φ = 7241472.

The previous prime is 18309923. The next prime is 18309979. The reversal of 18309928 is 82990381.

It can be written as a sum of positive squares in 2 ways, for example, as 16826404 + 1483524 = 4102^2 + 1218^2 .

It is not an unprimeable number, because it can be changed into a prime (18309923) 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 11 ways as a sum of consecutive naturals, for example, 3300 + ... + 6892.

Almost surely, 2^18309928 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 18309928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21510090).

18309928 is an abundant number, since it is smaller than the sum of its proper divisors (24710252).

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

18309928 is a wasteful number, since it uses less digits than its factorization.

18309928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3626 (or 3615 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 18309928 is about 4279.0101659145. The cubic root of 18309928 is about 263.5697383906.

The spelling of 18309928 in words is "eighteen million, three hundred nine thousand, nine hundred twenty-eight".