509986 has 4 divisors (see below), whose sum is σ = 764982. Its totient is φ = 254992.

The previous prime is 509963. The next prime is 509989. The reversal of 509986 is 689905.

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

It can be written as a sum of positive squares in only one way, i.e., 463761 + 46225 = 681^2 + 215^2 .

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 as a sum of consecutive naturals, namely, 127495 + ... + 127498.

2⁵⁰⁹⁹⁸⁶ is an apocalyptic number.

509986 is a deficient number, since it is larger than the sum of its proper divisors (254996).

509986 is a wasteful number, since it uses less digits than its factorization.

509986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254995.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 509986 is about 714.1330408264. The cubic root of 509986 is about 79.8949663261.

The spelling of 509986 in words is "five hundred nine thousand, nine hundred eighty-six".