18720030 has 64 divisors (see below), whose sum is σ = 51932160. Its totient is φ = 4230144.

The previous prime is 18719983. The next prime is 18720083. The reversal of 18720030 is 3002781.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18719979 and 18720006.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19911 + ... + 20829.

It is an arithmetic number, because the mean of its divisors is an integer number (811440).

Almost surely, 2^18720030 is an apocalyptic number.

18720030 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18720030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25966080).

18720030 is an abundant number, since it is smaller than the sum of its proper divisors (33212130).

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

18720030 is a wasteful number, since it uses less digits than its factorization.

18720030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1033.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 18720030 is about 4326.6649974316. The cubic root of 18720030 is about 265.5230206914.

The spelling of 18720030 in words is "eighteen million, seven hundred twenty thousand, thirty".