509989 has 2 divisors, whose sum is σ = 509990. Its totient is φ = 509988.

The previous prime is 509963. The next prime is 510007. The reversal of 509989 is 989905.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 293764 + 216225 = 542^2 + 465^2 .

It is a cyclic number.

It is not a de Polignac number, because 509989 - 2⁹ = 509477 is a prime.

509989 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (509909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254994 + 254995.

It is an arithmetic number, because the mean of its divisors is an integer number (254995).

2⁵⁰⁹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

509989 is a deficient number, since it is larger than the sum of its proper divisors (1).

509989 is an equidigital number, since it uses as much as digits as its factorization.

509989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 40.

The square root of 509989 is about 714.1351412723. The cubic root of 509989 is about 79.8951229869.

The spelling of 509989 in words is "five hundred nine thousand, nine hundred eighty-nine".