285440 has 36 divisors (see below), whose sum is σ = 686784. Its totient is φ = 113664.

The previous prime is 285433. The next prime is 285451. The reversal of 285440 is 44582.

285440 is nontrivially palindromic in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 285440.

It is an unprimeable number.

285440 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1169 + ... + 1391.

2²⁸⁵⁴⁴⁰ is an apocalyptic number.

285440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 285440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (343392).

285440 is an abundant number, since it is smaller than the sum of its proper divisors (401344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

285440 is an equidigital number, since it uses as much as digits as its factorization.

285440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 285440 is about 534.2658514260. The cubic root of 285440 is about 65.8422925726.

The spelling of 285440 in words is "two hundred eighty-five thousand, four hundred forty".