285720 has 32 divisors (see below), whose sum is σ = 857520. Its totient is φ = 76160.

The previous prime is 285709. The next prime is 285721. The reversal of 285720 is 27582.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a d-powerful number, because it can be written as 2¹¹ + 8⁴ + 7⁵ + 5⁴ + 2¹⁸ + 0 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285721) by changing a digit.

285720 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1071 + ... + 1310.

2²⁸⁵⁷²⁰ is an apocalyptic number.

285720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

285720 is an abundant number, since it is smaller than the sum of its proper divisors (571800).

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

285720 is a wasteful number, since it uses less digits than its factorization.

285720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2395 (or 2391 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 285720 is about 534.5278290230. The cubic root of 285720 is about 65.8638146871.

The spelling of 285720 in words is "two hundred eighty-five thousand, seven hundred twenty".