321680 has 20 divisors (see below), whose sum is σ = 748092. Its totient is φ = 128640.

The previous prime is 321679. The next prime is 321707. The reversal of 321680 is 86123.

It can be written as a sum of positive squares in 2 ways, for example, as 59536 + 262144 = 244^2 + 512^2 .

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

It is a Smith number, since the sum of its digits (20) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a nialpdrome in base 14.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 321680.

It is an unprimeable 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, 1931 + ... + 2090.

2³²¹⁶⁸⁰ is an apocalyptic number.

It is an amenable number.

321680 is an abundant number, since it is smaller than the sum of its proper divisors (426412).

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

321680 is a wasteful number, since it uses less digits than its factorization.

321680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4034 (or 4028 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 321680 is about 567.1684053260. The cubic root of 321680 is about 68.5185273201.

It can be divided in two parts, 321 and 680, that added together give a palindrome (1001).

The spelling of 321680 in words is "three hundred twenty-one thousand, six hundred eighty".