18009720 has 96 divisors (see below), whose sum is σ = 61635600. Its totient is φ = 4548096.

The previous prime is 18009683. The next prime is 18009763. The reversal of 18009720 is 2790081.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5524 + ... + 8156.

Almost surely, 2^18009720 is an apocalyptic number.

18009720 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 18009720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30817800).

18009720 is an abundant number, since it is smaller than the sum of its proper divisors (43625880).

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

18009720 is a wasteful number, since it uses less digits than its factorization.

18009720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2669 (or 2662 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 18009720 is about 4243.7860455023. The cubic root of 18009720 is about 262.1213042773.

The spelling of 18009720 in words is "eighteen million, nine thousand, seven hundred twenty".