18720000 has 270 divisors, whose sum is σ = 72634562. Its totient is φ = 4608000.

The previous prime is 18719983. The next prime is 18720083. The reversal of 18720000 is 2781.

It can be written as a sum of positive squares in 5 ways, for example, as 10969344 + 7750656 = 3312^2 + 2784^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 1439994 + ... + 1440006.

Almost surely, 2^18720000 is an apocalyptic number.

18720000 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 18720000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36317281).

18720000 is an abundant number, since it is smaller than the sum of its proper divisors (53914562).

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

18720000 is an equidigital number, since it uses as much as digits as its factorization.

18720000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55 (or 23 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 18720000 is about 4326.6615305568. The cubic root of 18720000 is about 265.5228788524.

Adding to 18720000 its reverse (2781), we get a palindrome (18722781).

It can be divided in two parts, 18 and 720000, that multiplied together give a 4-th power (12960000 = 60⁴).

The spelling of 18720000 in words is "eighteen million, seven hundred twenty thousand".