27681 has 4 divisors (see below), whose sum is σ = 36912. Its totient is φ = 18452.

The previous prime is 27673. The next prime is 27689. The reversal of 27681 is 18672.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (27673) and next prime (27689).

It is a cyclic number.

It is not a de Polignac number, because 27681 - 2³ = 27673 is a prime.

It is a super-2 number, since 2×27681² = 1532475522, which contains 22 as substring.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (27689) 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, 4611 + ... + 4616.

It is an arithmetic number, because the mean of its divisors is an integer number (9228).

2²⁷⁶⁸¹ is an apocalyptic number.

It is an amenable number.

27681 is a deficient number, since it is larger than the sum of its proper divisors (9231).

27681 is an equidigital number, since it uses as much as digits as its factorization.

27681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9230.

The product of its digits is 672, while the sum is 24.

The square root of 27681 is about 166.3760800115. The cubic root of 27681 is about 30.2501309103.

Subtracting from 27681 its reverse (18672), we obtain a palindrome (9009).

The spelling of 27681 in words is "twenty-seven thousand, six hundred eighty-one".