18320400 has 180 divisors, whose sum is σ = 72759232. Its totient is φ = 4181760.

The previous prime is 18320387. The next prime is 18320417. The reversal of 18320400 is 402381.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (180).

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 24837 + ... + 25563.

Almost surely, 2^18320400 is an apocalyptic number.

18320400 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 18320400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36379616).

18320400 is an abundant number, since it is smaller than the sum of its proper divisors (54438832).

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

18320400 is a wasteful number, since it uses less digits than its factorization.

18320400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758 (or 744 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 18320400 is about 4280.2336384828. The cubic root of 18320400 is about 263.6199766415.

Adding to 18320400 its reverse (402381), we get a palindrome (18722781).

The spelling of 18320400 in words is "eighteen million, three hundred twenty thousand, four hundred".