27021 has 4 divisors (see below), whose sum is σ = 36032. Its totient is φ = 18012.

The previous prime is 27017. The next prime is 27031. The reversal of 27021 is 12072.

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 27021 - 2² = 27017 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a junction number, because it is equal to n+sod(n) for n = 26988 and 27006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27011) 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, 4501 + ... + 4506.

It is an arithmetic number, because the mean of its divisors is an integer number (9008).

2²⁷⁰²¹ is an apocalyptic number.

It is an amenable number.

27021 is a deficient number, since it is larger than the sum of its proper divisors (9011).

27021 is an equidigital number, since it uses as much as digits as its factorization.

27021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9010.

The product of its (nonzero) digits is 28, while the sum is 12.

The square root of 27021 is about 164.3806557962. The cubic root of 27021 is about 30.0077757622.

Adding to 27021 its reverse (12072), we get a palindrome (39093).

The spelling of 27021 in words is "twenty-seven thousand, twenty-one", and thus it is an iban number.