285689 has 4 divisors (see below), whose sum is σ = 288420. Its totient is φ = 282960.

The previous prime is 285673. The next prime is 285697. The reversal of 285689 is 986582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 986582 = 2 ⋅493291.

It can be written as a sum of positive squares in 2 ways, for example, as 218089 + 67600 = 467^2 + 260^2 .

It is a cyclic number.

It is not a de Polignac number, because 285689 - 2⁴ = 285673 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (285629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1202 + ... + 1419.

It is an arithmetic number, because the mean of its divisors is an integer number (72105).

2²⁸⁵⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

285689 is a deficient number, since it is larger than the sum of its proper divisors (2731).

285689 is a wasteful number, since it uses less digits than its factorization.

285689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2730.

The product of its digits is 34560, while the sum is 38.

The square root of 285689 is about 534.4988306816. The cubic root of 285689 is about 65.8614325739.

The spelling of 285689 in words is "two hundred eighty-five thousand, six hundred eighty-nine".