1638320 has 20 divisors (see below), whose sum is σ = 3809280. Its totient is φ = 655296.

The previous prime is 1638311. The next prime is 1638331. The reversal of 1638320 is 238361.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10160 + ... + 10319.

It is an arithmetic number, because the mean of its divisors is an integer number (190464).

2^1638320 is an apocalyptic number.

1638320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638320 is an abundant number, since it is smaller than the sum of its proper divisors (2170960).

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

1638320 is a wasteful number, since it uses less digits than its factorization.

1638320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20492 (or 20486 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 1638320 is about 1279.9687496185. The cubic root of 1638320 is about 117.8870891589.

The spelling of 1638320 in words is "one million, six hundred thirty-eight thousand, three hundred twenty".