18109720 has 32 divisors (see below), whose sum is σ = 41212800. Its totient is φ = 7161088.

The previous prime is 18109703. The next prime is 18109727. The reversal of 18109720 is 2790181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18109727) 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, 1017 + ... + 6103.

It is an arithmetic number, because the mean of its divisors is an integer number (1287900).

Almost surely, 2^18109720 is an apocalyptic number.

18109720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18109720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20606400).

18109720 is an abundant number, since it is smaller than the sum of its proper divisors (23103080).

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

18109720 is a wasteful number, since it uses less digits than its factorization.

18109720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5187 (or 5183 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 18109720 is about 4255.5516681154. The cubic root of 18109720 is about 262.6055569429.

The spelling of 18109720 in words is "eighteen million, one hundred nine thousand, seven hundred twenty".