285309 has 8 divisors (see below), whose sum is σ = 422720. Its totient is φ = 190188.

The previous prime is 285301. The next prime is 285317. The reversal of 285309 is 903582.

It is an interprime number because it is at equal distance from previous prime (285301) and next prime (285317).

It is not a de Polignac number, because 285309 - 2³ = 285301 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 10567 = 285309 / (2 + 8 + 5 + 3 + 0 + 9).

It is a Duffinian number.

285309 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5257 + ... + 5310.

It is an arithmetic number, because the mean of its divisors is an integer number (52840).

2²⁸⁵³⁰⁹ is an apocalyptic number.

It is an amenable number.

285309 is a deficient number, since it is larger than the sum of its proper divisors (137411).

285309 is a wasteful number, since it uses less digits than its factorization.

285309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10576 (or 10570 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 285309 is about 534.1432392158. The cubic root of 285309 is about 65.8322184646.

The spelling of 285309 in words is "two hundred eighty-five thousand, three hundred nine".