18432640 has 64 divisors (see below), whose sum is σ = 44724960. Its totient is φ = 7263232.

The previous prime is 18432629. The next prime is 18432647. The reversal of 18432640 is 4623481.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 18432599 and 18432608.

It is not an unprimeable number, because it can be changed into a prime (18432647) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 52947 + ... + 53293.

Almost surely, 2^18432640 is an apocalyptic number.

18432640 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 18432640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22362480).

18432640 is an abundant number, since it is smaller than the sum of its proper divisors (26292320).

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

18432640 is an equidigital number, since it uses as much as digits as its factorization.

18432640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 449 (or 437 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 18432640 is about 4293.3250517518. The cubic root of 18432640 is about 264.1572372162.

The spelling of 18432640 in words is "eighteen million, four hundred thirty-two thousand, six hundred forty".