285940 has 36 divisors (see below), whose sum is σ = 658476. Its totient is φ = 103936.

The previous prime is 285937. The next prime is 285949. The reversal of 285940 is 49582.

285940 = T₁₅₉ + T₁₆₀ + ... + T₁₇₈.

285940 = 131² + 132² + ... + 145².

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2916 + 283024 = 54^2 + 532^2 .

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 285899 and 285908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285949) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9846 + ... + 9874.

It is an arithmetic number, because the mean of its divisors is an integer number (18291).

2²⁸⁵⁹⁴⁰ is an apocalyptic number.

285940 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 285940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329238).

285940 is an abundant number, since it is smaller than the sum of its proper divisors (372536).

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

285940 is a wasteful number, since it uses less digits than its factorization.

285940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 285940 is about 534.7335785230. The cubic root of 285940 is about 65.8807150578.

It can be divided in two parts, 285 and 940, that added together give a triangular number (1225 = T₄₉).

The spelling of 285940 in words is "two hundred eighty-five thousand, nine hundred forty".