287861 has 16 divisors (see below), whose sum is σ = 362880. Its totient is φ = 222720.

The previous prime is 287857. The next prime is 287863. The reversal of 287861 is 168782.

It is a cyclic number.

It is not a de Polignac number, because 287861 - 2² = 287857 is a prime.

287861 is a modest number, since divided by 861 gives 287 as remainder.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4850 + ... + 4908.

It is an arithmetic number, because the mean of its divisors is an integer number (22680).

2²⁸⁷⁸⁶¹ is an apocalyptic number.

It is an amenable number.

287861 is a deficient number, since it is larger than the sum of its proper divisors (75019).

287861 is a wasteful number, since it uses less digits than its factorization.

287861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124.

The product of its digits is 5376, while the sum is 32.

The square root of 287861 is about 536.5267933664. The cubic root of 287861 is about 66.0279190116.

The spelling of 287861 in words is "two hundred eighty-seven thousand, eight hundred sixty-one".