287381 has 4 divisors (see below), whose sum is σ = 290700. Its totient is φ = 284064.

The previous prime is 287347. The next prime is 287383. The reversal of 287381 is 183782.

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 70225 + 217156 = 265^2 + 466^2 .

It is a cyclic number.

It is not a de Polignac number, because 287381 - 2¹⁸ = 25237 is a prime.

It is a super-2 number, since 2×287381² = 165175678322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 287381.

It is not an unprimeable number, because it can be changed into a prime (287383) 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, 1526 + ... + 1703.

It is an arithmetic number, because the mean of its divisors is an integer number (72675).

2²⁸⁷³⁸¹ is an apocalyptic number.

It is an amenable number.

287381 is a deficient number, since it is larger than the sum of its proper divisors (3319).

287381 is an equidigital number, since it uses as much as digits as its factorization.

287381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3318.

The product of its digits is 2688, while the sum is 29.

The square root of 287381 is about 536.0792851808. The cubic root of 287381 is about 65.9911987039.

The spelling of 287381 in words is "two hundred eighty-seven thousand, three hundred eighty-one".