281805 has 8 divisors (see below), whose sum is σ = 450912. Its totient is φ = 150288.

The previous prime is 281803. The next prime is 281807. The reversal of 281805 is 508182.

It is an interprime number because it is at equal distance from previous prime (281803) and next prime (281807).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 281805 - 2¹ = 281803 is a prime.

It is a plaindrome in base 16.

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 281805.

It is not an unprimeable number, because it can be changed into a prime (281803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9379 + ... + 9408.

It is an arithmetic number, because the mean of its divisors is an integer number (56364).

2²⁸¹⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

281805 is a deficient number, since it is larger than the sum of its proper divisors (169107).

281805 is a wasteful number, since it uses less digits than its factorization.

281805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18795.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 281805 is about 530.8530870213. The cubic root of 281805 is about 65.5616031745.

Adding to 281805 its reverse (508182), we get a palindrome (789987).

The spelling of 281805 in words is "two hundred eighty-one thousand, eight hundred five".