509161 has 4 divisors (see below), whose sum is σ = 511632. Its totient is φ = 506692.

The previous prime is 509149. The next prime is 509203. The reversal of 509161 is 161905.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 161905 = 5 ⋅32381.

It is a cyclic number.

It is not a de Polignac number, because 509161 - 2¹¹ = 507113 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (509101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 895 + ... + 1348.

It is an arithmetic number, because the mean of its divisors is an integer number (127908).

2⁵⁰⁹¹⁶¹ is an apocalyptic number.

It is an amenable number.

509161 is a deficient number, since it is larger than the sum of its proper divisors (2471).

509161 is a wasteful number, since it uses less digits than its factorization.

509161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2470.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 509161 is about 713.5551835703. Note that the first 3 decimals coincide. The cubic root of 509161 is about 79.8518612725.

The spelling of 509161 in words is "five hundred nine thousand, one hundred sixty-one".