509081 has 4 divisors (see below), whose sum is σ = 510564. Its totient is φ = 507600.

The previous prime is 509071. The next prime is 509087. The reversal of 509081 is 180905.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 259081 + 250000 = 509^2 + 500^2 .

It is a cyclic number.

It is not a de Polignac number, because 509081 - 2¹⁸ = 246937 is a prime.

It is a super-2 number, since 2×509081² = 518326929122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (509087) 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, 71 + ... + 1011.

It is an arithmetic number, because the mean of its divisors is an integer number (127641).

2⁵⁰⁹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

509081 is a deficient number, since it is larger than the sum of its proper divisors (1483).

509081 is an equidigital number, since it uses as much as digits as its factorization.

509081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1482.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 509081 is about 713.4991240359. The cubic root of 509081 is about 79.8476789126.

Adding to 509081 its reverse (180905), we get a palindrome (689986).

The spelling of 509081 in words is "five hundred nine thousand, eighty-one".