285865 has 4 divisors (see below), whose sum is σ = 343044. Its totient is φ = 228688.

The previous prime is 285841. The next prime is 285871. The reversal of 285865 is 568582.

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

It can be written as a sum of positive squares in 2 ways, for example, as 205209 + 80656 = 453^2 + 284^2 .

It is a cyclic number.

It is not a de Polignac number, because 285865 - 2¹¹ = 283817 is a prime.

It is a Duffinian number.

285865 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 285865.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28582 + ... + 28591.

It is an arithmetic number, because the mean of its divisors is an integer number (85761).

2²⁸⁵⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

285865 is a deficient number, since it is larger than the sum of its proper divisors (57179).

285865 is an equidigital number, since it uses as much as digits as its factorization.

285865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57178.

The product of its digits is 19200, while the sum is 34.

The square root of 285865 is about 534.6634455431. The cubic root of 285865 is about 65.8749545420.

The spelling of 285865 in words is "two hundred eighty-five thousand, eight hundred sixty-five".