287989 has 4 divisors (see below), whose sum is σ = 310156. Its totient is φ = 265824.

The previous prime is 287977. The next prime is 288007. The reversal of 287989 is 989782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27889 + 260100 = 167^2 + 510^2 .

It is a de Polignac number, because none of the positive numbers 2^k-287989 is a prime.

It is a Duffinian number.

287989 is a lucky number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11064 + ... + 11089.

It is an arithmetic number, because the mean of its divisors is an integer number (77539).

2²⁸⁷⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

287989 is a deficient number, since it is larger than the sum of its proper divisors (22167).

287989 is a wasteful number, since it uses less digits than its factorization.

287989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22166.

The product of its digits is 72576, while the sum is 43.

The square root of 287989 is about 536.6460658572. The cubic root of 287989 is about 66.0377041987.

The spelling of 287989 in words is "two hundred eighty-seven thousand, nine hundred eighty-nine".