287820 has 96 divisors (see below), whose sum is σ = 987840. Its totient is φ = 69120.

The previous prime is 287813. The next prime is 287821. The reversal of 287820 is 28782.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287821) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 7000 + ... + 7040.

It is an arithmetic number, because the mean of its divisors is an integer number (10290).

2²⁸⁷⁸²⁰ is an apocalyptic number.

287820 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 287820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (493920).

287820 is an abundant number, since it is smaller than the sum of its proper divisors (700020).

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

287820 is a wasteful number, since it uses less digits than its factorization.

287820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 287820 is about 536.4885832895. The cubic root of 287820 is about 66.0247840804.

The spelling of 287820 in words is "two hundred eighty-seven thousand, eight hundred twenty".