287881 has 4 divisors (see below), whose sum is σ = 314064. Its totient is φ = 261700.

The previous prime is 287873. The next prime is 287887. The reversal of 287881 is 188782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 287881 - 2³ = 287873 is a prime.

It is a super-2 number, since 2×287881² = 165750940322, which contains 22 as substring.

It is a Duffinian number.

287881 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (287887) 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 3 ways as a sum of consecutive naturals, for example, 13075 + ... + 13096.

It is an arithmetic number, because the mean of its divisors is an integer number (78516).

2²⁸⁷⁸⁸¹ is an apocalyptic number.

It is an amenable number.

287881 is a deficient number, since it is larger than the sum of its proper divisors (26183).

287881 is a wasteful number, since it uses less digits than its factorization.

287881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26182.

The product of its digits is 7168, while the sum is 34.

The square root of 287881 is about 536.5454314408. The cubic root of 287881 is about 66.0294481382.

Subtracting from 287881 its reverse (188782), we obtain a palindrome (99099).

The spelling of 287881 in words is "two hundred eighty-seven thousand, eight hundred eighty-one".