• 320 can be written using four 4's:

See also 113.

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320 has 14 divisors (see below), whose sum is σ = 762. Its totient is φ = 128.

The previous prime is 317. The next prime is 331. The reversal of 320 is 23.

Added to its reverse (23) it gives a cube (343 = 7³).

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 256 + 64 = 16^2 + 8^2 .

It is a Harshad number since it is a multiple of its sum of digits (5).

It is a Leyland number of the form 8² + 2⁸.

It is a plaindrome in base 12 and base 14.

It is a nialpdrome in base 4, base 8 and base 10.

It is a zygodrome in base 4.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (2) of ones.

In principle, a polygon with 320 sides can be constructed with ruler and compass.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62 + ... + 66.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (381).

320 is an abundant number, since it is smaller than the sum of its proper divisors (442).

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

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

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

The sum of its prime factors is 17 (or 7 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 5.

The square root of 320 is about 17.8885438200. Note that the first 3 decimals coincide. The cubic root of 320 is about 6.8399037867.

Adding to 320 its reverse (23), we get a palindrome (343).

The spelling of 320 in words is "three hundred twenty", and thus it is an aban number, an iban number, and an oban number.