509685 has 16 divisors (see below), whose sum is σ = 889920. Its totient is φ = 247040.

The previous prime is 509681. The next prime is 509687. The reversal of 509685 is 586905.

It is not a de Polignac number, because 509685 - 2² = 509681 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1380 + ... + 1709.

It is an arithmetic number, because the mean of its divisors is an integer number (55620).

2⁵⁰⁹⁶⁸⁵ is an apocalyptic number.

509685 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

509685 is a deficient number, since it is larger than the sum of its proper divisors (380235).

509685 is a wasteful number, since it uses less digits than its factorization.

509685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3108.

The product of its (nonzero) digits is 10800, while the sum is 33.

The square root of 509685 is about 713.9222646759. The cubic root of 509685 is about 79.8792449026.

The spelling of 509685 in words is "five hundred nine thousand, six hundred eighty-five".