18072720 has 100 divisors (see below), whose sum is σ = 62791740. Its totient is φ = 4817664.

The previous prime is 18072707. The next prime is 18072739. The reversal of 18072720 is 2727081.

It can be written as a sum of positive squares in 2 ways, for example, as 8928144 + 9144576 = 2988^2 + 3024^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5086 + ... + 7874.

Almost surely, 2^18072720 is an apocalyptic number.

18072720 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 18072720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31395870).

18072720 is an abundant number, since it is smaller than the sum of its proper divisors (44719020).

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

18072720 is a wasteful number, since it uses less digits than its factorization.

18072720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2814 (or 2799 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 18072720 is about 4251.2021829125. The cubic root of 18072720 is about 262.4265917181.

It can be divided in two parts, 180 and 72720, that added together give a square (72900 = 270²).

The spelling of 18072720 in words is "eighteen million, seventy-two thousand, seven hundred twenty".