281587 has 4 divisors (see below), whose sum is σ = 283240. Its totient is φ = 279936.

The previous prime is 281581. The next prime is 281609. The reversal of 281587 is 785182.

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

It is a 7-Lehmer number, since φ(281587) divides (281587-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 281587 - 2³ = 281579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (281581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 537 + ... + 922.

It is an arithmetic number, because the mean of its divisors is an integer number (70810).

2²⁸¹⁵⁸⁷ is an apocalyptic number.

281587 is a deficient number, since it is larger than the sum of its proper divisors (1653).

281587 is a wasteful number, since it uses less digits than its factorization.

281587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1652.

The product of its digits is 4480, while the sum is 31.

The square root of 281587 is about 530.6477174171. The cubic root of 281587 is about 65.5446929984.

It can be divided in two parts, 281 and 587, that added together give a palindrome (868).

The spelling of 281587 in words is "two hundred eighty-one thousand, five hundred eighty-seven".