285921 has 6 divisors (see below), whose sum is σ = 413010. Its totient is φ = 190608.

The previous prime is 285871. The next prime is 285937. The reversal of 285921 is 129582.

It can be written as a sum of positive squares in only one way, i.e., 216225 + 69696 = 465^2 + 264^2 .

It is not a de Polignac number, because 285921 - 2¹⁰ = 284897 is a prime.

It is an Ulam number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 285921.

It is not an unprimeable number, because it can be changed into a prime (285121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 15876 + ... + 15893.

It is an arithmetic number, because the mean of its divisors is an integer number (68835).

2²⁸⁵⁹²¹ is an apocalyptic number.

It is an amenable number.

285921 is a deficient number, since it is larger than the sum of its proper divisors (127089).

285921 is a wasteful number, since it uses less digits than its factorization.

285921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31775 (or 31772 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 285921 is about 534.7158123714. The cubic root of 285921 is about 65.8792558224.

The spelling of 285921 in words is "two hundred eighty-five thousand, nine hundred twenty-one".