509866 has 16 divisors (see below), whose sum is σ = 887040. Its totient is φ = 215280.

The previous prime is 509863. The next prime is 509867. The reversal of 509866 is 668905.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (509863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 876 + ... + 1336.

It is an arithmetic number, because the mean of its divisors is an integer number (55440).

2⁵⁰⁹⁸⁶⁶ is an apocalyptic number.

509866 is a deficient number, since it is larger than the sum of its proper divisors (377174).

509866 is a wasteful number, since it uses less digits than its factorization.

509866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 509866 is about 714.0490179252. The cubic root of 509866 is about 79.8886993907. Note that the first 3 decimals are identical.

The spelling of 509866 in words is "five hundred nine thousand, eight hundred sixty-six".