321391 has 8 divisors (see below), whose sum is σ = 375200. Its totient is φ = 275184.

The previous prime is 321383. The next prime is 321397. The reversal of 321391 is 193123.

It is not a de Polignac number, because 321391 - 2³ = 321383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126 + ... + 811.

It is an arithmetic number, because the mean of its divisors is an integer number (46900).

2³²¹³⁹¹ is an apocalyptic number.

321391 is a deficient number, since it is larger than the sum of its proper divisors (53809).

321391 is an frugal number, since it uses more digits than its factorization.

321391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 958 (or 944 counting only the distinct ones).

The product of its digits is 162, while the sum is 19.

The square root of 321391 is about 566.9135736600. The cubic root of 321391 is about 68.4980019663.

The spelling of 321391 in words is "three hundred twenty-one thousand, three hundred ninety-one".