509987 has 4 divisors (see below), whose sum is σ = 512616. Its totient is φ = 507360.

The previous prime is 509963. The next prime is 509989. The reversal of 509987 is 789905.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 509987 - 2⁸ = 509731 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 509987.

It is not an unprimeable number, because it can be changed into a prime (509989) 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, 998 + ... + 1419.

It is an arithmetic number, because the mean of its divisors is an integer number (128154).

2⁵⁰⁹⁹⁸⁷ is an apocalyptic number.

509987 is a deficient number, since it is larger than the sum of its proper divisors (2629).

509987 is a wasteful number, since it uses less digits than its factorization.

509987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2628.

The product of its (nonzero) digits is 22680, while the sum is 38.

The square root of 509987 is about 714.1337409757. The cubic root of 509987 is about 79.8950185464.

The spelling of 509987 in words is "five hundred nine thousand, nine hundred eighty-seven".