509813 has 4 divisors (see below), whose sum is σ = 539820. Its totient is φ = 479808.

The previous prime is 509801. The next prime is 509833. The reversal of 509813 is 318905.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 318905 = 5 ⋅63781.

It can be written as a sum of positive squares in 2 ways, for example, as 418609 + 91204 = 647^2 + 302^2 .

It is not a de Polignac number, because 509813 - 2⁴ = 509797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509833) 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 3 ways as a sum of consecutive naturals, for example, 14978 + ... + 15011.

It is an arithmetic number, because the mean of its divisors is an integer number (134955).

2⁵⁰⁹⁸¹³ is an apocalyptic number.

It is an amenable number.

509813 is a deficient number, since it is larger than the sum of its proper divisors (30007).

509813 is a wasteful number, since it uses less digits than its factorization.

509813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30006.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 509813 is about 714.0119046627. The cubic root of 509813 is about 79.8859311811.

The spelling of 509813 in words is "five hundred nine thousand, eight hundred thirteen".