281681 has 8 divisors (see below), whose sum is σ = 302784. Its totient is φ = 261360.

The previous prime is 281669. The next prime is 281683. The reversal of 281681 is 186182.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-281681 is a prime.

It is a super-2 number, since 2×281681² = 158688371522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 281681.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 281681.

It is not an unprimeable number, because it can be changed into a prime (281683) 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 7 ways as a sum of consecutive naturals, for example, 686 + ... + 1016.

It is an arithmetic number, because the mean of its divisors is an integer number (37848).

2²⁸¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

281681 is a deficient number, since it is larger than the sum of its proper divisors (21103).

281681 is a wasteful number, since it uses less digits than its factorization.

281681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391.

The product of its digits is 768, while the sum is 26.

The square root of 281681 is about 530.7362810285. The cubic root of 281681 is about 65.5519856121.

The spelling of 281681 in words is "two hundred eighty-one thousand, six hundred eighty-one".