509581 has 2 divisors, whose sum is σ = 509582. Its totient is φ = 509580.

The previous prime is 509573. The next prime is 509591. The reversal of 509581 is 185905.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 320356 + 189225 = 566^2 + 435^2 .

It is a cyclic number.

It is not a de Polignac number, because 509581 - 2³ = 509573 is a prime.

It is a super-2 number, since 2×509581² = 519345591122, which contains 22 as substring.

It is an Ulam number.

509581 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (509521) 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 as a sum of consecutive naturals, namely, 254790 + 254791.

It is an arithmetic number, because the mean of its divisors is an integer number (254791).

2⁵⁰⁹⁵⁸¹ is an apocalyptic number.

It is an amenable number.

509581 is a deficient number, since it is larger than the sum of its proper divisors (1).

509581 is an equidigital number, since it uses as much as digits as its factorization.

509581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 28.

The square root of 509581 is about 713.8494238983. The cubic root of 509581 is about 79.8738114770.

The spelling of 509581 in words is "five hundred nine thousand, five hundred eighty-one".