320921 has 4 divisors (see below), whose sum is σ = 326244. Its totient is φ = 315600.

The previous prime is 320911. The next prime is 320923. The reversal of 320921 is 129023.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 105625 + 215296 = 325^2 + 464^2 .

It is a cyclic number.

It is not a de Polignac number, because 320921 - 2¹⁰ = 319897 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 320921.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 320921.

It is not an unprimeable number, because it can be changed into a prime (320923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2570 + ... + 2691.

It is an arithmetic number, because the mean of its divisors is an integer number (81561).

2³²⁰⁹²¹ is an apocalyptic number.

It is an amenable number.

320921 is a deficient number, since it is larger than the sum of its proper divisors (5323).

320921 is an equidigital number, since it uses as much as digits as its factorization.

320921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5322.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 320921 is about 566.4988967333. The cubic root of 320921 is about 68.4645953400.

Adding to 320921 its reverse (129023), we get a palindrome (449944).

The spelling of 320921 in words is "three hundred twenty thousand, nine hundred twenty-one".