321280 has 36 divisors (see below), whose sum is σ = 772632. Its totient is φ = 128000.

The previous prime is 321247. The next prime is 321289. The reversal of 321280 is 82123.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321289) by changing a digit.

321280 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 3 ways as a sum of consecutive naturals, for example, 1155 + ... + 1405.

It is an arithmetic number, because the mean of its divisors is an integer number (21462).

2³²¹²⁸⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 321280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (386316).

321280 is an abundant number, since it is smaller than the sum of its proper divisors (451352).

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

321280 is an equidigital number, since it uses as much as digits as its factorization.

321280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272 (or 258 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 321280 is about 566.8156666854. The cubic root of 321280 is about 68.4901152554.

The spelling of 321280 in words is "three hundred twenty-one thousand, two hundred eighty".