27381 has 4 divisors (see below), whose sum is σ = 36512. Its totient is φ = 18252.

The previous prime is 27367. The next prime is 27397. The reversal of 27381 is 18372.

Added to its reverse (18372) it gives a triangular number (45753 = T₃₀₂).

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 not a de Polignac number, because 27381 - 2⁷ = 27253 is a prime.

It is a super-2 number, since 2×27381² = 1499438322, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27361) 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, 4561 + ... + 4566.

It is an arithmetic number, because the mean of its divisors is an integer number (9128).

2²⁷³⁸¹ is an apocalyptic number.

It is an amenable number.

27381 is a deficient number, since it is larger than the sum of its proper divisors (9131).

27381 is an equidigital number, since it uses as much as digits as its factorization.

27381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9130.

The product of its digits is 336, while the sum is 21.

The square root of 27381 is about 165.4720520209. The cubic root of 27381 is about 30.1404525212.

Adding to 27381 its reverse (18372), we get a triangular number (45753 = T₃₀₂).

Subtracting from 27381 its reverse (18372), we obtain a palindrome (9009).

The spelling of 27381 in words is "twenty-seven thousand, three hundred eighty-one".