509791 has 4 divisors (see below), whose sum is σ = 527400. Its totient is φ = 492184.

The previous prime is 509783. The next prime is 509797. The reversal of 509791 is 197905.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197905 = 5 ⋅39581.

It is a cyclic number.

It is not a de Polignac number, because 509791 - 2³ = 509783 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 (509797) 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, 8761 + ... + 8818.

It is an arithmetic number, because the mean of its divisors is an integer number (131850).

2⁵⁰⁹⁷⁹¹ is an apocalyptic number.

509791 is a deficient number, since it is larger than the sum of its proper divisors (17609).

509791 is a wasteful number, since it uses less digits than its factorization.

509791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17608.

The product of its (nonzero) digits is 2835, while the sum is 31.

The square root of 509791 is about 713.9964985909. The cubic root of 509791 is about 79.8847820566.

The spelling of 509791 in words is "five hundred nine thousand, seven hundred ninety-one".