27691 has 2 divisors, whose sum is σ = 27692. Its totient is φ = 27690.

The previous prime is 27689. The next prime is 27697. The reversal of 27691 is 19672.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 27691 - 2¹ = 27689 is a prime.

Together with 27689, it forms a pair of twin primes.

27691 is a lucky number.

It is a nialpdrome in base 6 and base 15.

It is not a weakly prime, because it can be changed into another prime (27697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13845 + 13846.

It is an arithmetic number, because the mean of its divisors is an integer number (13846).

2²⁷⁶⁹¹ is an apocalyptic number.

27691 is a deficient number, since it is larger than the sum of its proper divisors (1).

27691 is an equidigital number, since it uses as much as digits as its factorization.

27691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 756, while the sum is 25.

The square root of 27691 is about 166.4061296948. The cubic root of 27691 is about 30.2537731787.

The spelling of 27691 in words is "twenty-seven thousand, six hundred ninety-one".