320640 has 64 divisors (see below), whose sum is σ = 1028160. Its totient is φ = 84992.

The previous prime is 320627. The next prime is 320647. The reversal of 320640 is 46023.

320640 is nontrivially palindromic in base 11.

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

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 320640.

It is not an unprimeable number, because it can be changed into a prime (320647) by changing a digit.

320640 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1837 + ... + 2003.

It is an arithmetic number, because the mean of its divisors is an integer number (16065).

2³²⁰⁶⁴⁰ is an apocalyptic number.

320640 is a gapful number since it is divisible by the number (30) 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 320640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (514080).

320640 is an abundant number, since it is smaller than the sum of its proper divisors (707520).

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

320640 is a wasteful number, since it uses less digits than its factorization.

320640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189 (or 177 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 320640 is about 566.2508278140. The cubic root of 320640 is about 68.4446068598. Note that the first 3 decimals are identical.

Adding to 320640 its reverse (46023), we get a palindrome (366663).

The spelling of 320640 in words is "three hundred twenty thousand, six hundred forty".