18400320 has 84 divisors (see below), whose sum is σ = 63299340. Its totient is φ = 4905984.

The previous prime is 18400313. The next prime is 18400351. The reversal of 18400320 is 2300481.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2143296 + 16257024 = 1464^2 + 4032^2 .

It is a super-2 number, since 2×18400320² = 677143552204800, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 18400293 and 18400302.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 315 + ... + 6074.

Almost surely, 2^18400320 is an apocalyptic number.

18400320 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 18400320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31649670).

18400320 is an abundant number, since it is smaller than the sum of its proper divisors (44899020).

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

18400320 is a wasteful number, since it uses less digits than its factorization.

18400320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6412 (or 6399 counting only the distinct ones).

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

The square root of 18400320 is about 4289.5594179356. The cubic root of 18400320 is about 264.0027547922.

The spelling of 18400320 in words is "eighteen million, four hundred thousand, three hundred twenty".