285665820 has 96 divisors (see below), whose sum is σ = 875508480. Its totient is φ = 69020160.

The previous prime is 285665797. The next prime is 285665833. The reversal of 285665820 is 28566582.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 276024 + ... + 277056.

It is an arithmetic number, because the mean of its divisors is an integer number (9119880).

Almost surely, 2^285665820 is an apocalyptic number.

285665820 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 285665820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (437754240).

285665820 is an abundant number, since it is smaller than the sum of its proper divisors (589842660).

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

285665820 is a wasteful number, since it uses less digits than its factorization.

285665820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1475 (or 1473 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 42.

The square root of 285665820 is about 16901.6513986060. The cubic root of 285665820 is about 658.5965125544.

The spelling of 285665820 in words is "two hundred eighty-five million, six hundred sixty-five thousand, eight hundred twenty".