321921 has 8 divisors (see below), whose sum is σ = 476960. Its totient is φ = 214596.

The previous prime is 321911. The next prime is 321947. The reversal of 321921 is 129123.

It is a happy number.

It is not a de Polignac number, because 321921 - 2⁵ = 321889 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 321894 and 321903.

It is not an unprimeable number, because it can be changed into a prime (321901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5935 + ... + 5988.

It is an arithmetic number, because the mean of its divisors is an integer number (59620).

2³²¹⁹²¹ is an apocalyptic number.

It is an amenable number.

321921 is a deficient number, since it is larger than the sum of its proper divisors (155039).

321921 is a wasteful number, since it uses less digits than its factorization.

321921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11932 (or 11926 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 321921 is about 567.3808244909. The cubic root of 321921 is about 68.5356342204.

It can be divided in two parts, 3219 and 21, that added together give a triangular number (3240 = T₈₀).

The spelling of 321921 in words is "three hundred twenty-one thousand, nine hundred twenty-one".