18328720 has 40 divisors (see below), whose sum is σ = 45124344. Its totient is φ = 6899712.

The previous prime is 18328693. The next prime is 18328729. The reversal of 18328720 is 2782381.

It can be written as a sum of positive squares in 4 ways, for example, as 5253264 + 13075456 = 2292^2 + 3616^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (18328729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5379 + ... + 8098.

Almost surely, 2^18328720 is an apocalyptic number.

18328720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18328720 is an abundant number, since it is smaller than the sum of its proper divisors (26795624).

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

18328720 is a wasteful number, since it uses less digits than its factorization.

18328720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13507 (or 13501 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 18328720 is about 4281.2054377243. The cubic root of 18328720 is about 263.6598772672.

The spelling of 18328720 in words is "eighteen million, three hundred twenty-eight thousand, seven hundred twenty".