285520 has 40 divisors (see below), whose sum is σ = 687456. Its totient is φ = 110208.

The previous prime is 285517. The next prime is 285521. The reversal of 285520 is 25582.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 285491 and 285500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3399 + ... + 3481.

2²⁸⁵⁵²⁰ is an apocalyptic number.

285520 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 285520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (343728).

285520 is an abundant number, since it is smaller than the sum of its proper divisors (401936).

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

285520 is a wasteful number, since it uses less digits than its factorization.

285520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 285520 is about 534.3407152744. The cubic root of 285520 is about 65.8484431838.

The spelling of 285520 in words is "two hundred eighty-five thousand, five hundred twenty".