287720 has 16 divisors (see below), whose sum is σ = 647460. Its totient is φ = 115072.

The previous prime is 287701. The next prime is 287731. The reversal of 287720 is 27782.

It can be written as a sum of positive squares in 2 ways, for example, as 256036 + 31684 = 506^2 + 178^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 287720.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 287720.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3557 + ... + 3636.

2²⁸⁷⁷²⁰ is an apocalyptic number.

287720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

287720 is an abundant number, since it is smaller than the sum of its proper divisors (359740).

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

287720 is a wasteful number, since it uses less digits than its factorization.

287720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7204 (or 7200 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 26.

The square root of 287720 is about 536.3953765647. The cubic root of 287720 is about 66.0171366582.

The spelling of 287720 in words is "two hundred eighty-seven thousand, seven hundred twenty".