509321 has 4 divisors (see below), whose sum is σ = 516372. Its totient is φ = 502272.

The previous prime is 509317. The next prime is 509329. The reversal of 509321 is 123905.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 123905 = 5 ⋅24781.

It can be written as a sum of positive squares in 2 ways, for example, as 190096 + 319225 = 436^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 509321 - 2² = 509317 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 509293 and 509302.

It is not an unprimeable number, because it can be changed into a prime (509329) 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, 3416 + ... + 3561.

It is an arithmetic number, because the mean of its divisors is an integer number (129093).

2⁵⁰⁹³²¹ is an apocalyptic number.

It is an amenable number.

509321 is a deficient number, since it is larger than the sum of its proper divisors (7051).

509321 is an equidigital number, since it uses as much as digits as its factorization.

509321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7050.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 509321 is about 713.6672894283. The cubic root of 509321 is about 79.8602246780.

It can be divided in two parts, 5093 and 21, that multiplied together give a triangular number (106953 = T₄₆₂).

The spelling of 509321 in words is "five hundred nine thousand, three hundred twenty-one".