21167 has 4 divisors (see below), whose sum is σ = 21576. Its totient is φ = 20760.

The previous prime is 21163. The next prime is 21169. The reversal of 21167 is 76112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21167 - 2² = 21163 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21163) 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, 113 + ... + 234.

It is an arithmetic number, because the mean of its divisors is an integer number (5394).

2²¹¹⁶⁷ is an apocalyptic number.

21167 is a deficient number, since it is larger than the sum of its proper divisors (409).

21167 is an equidigital number, since it uses as much as digits as its factorization.

21167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408.

The product of its digits is 84, while the sum is 17.

The square root of 21167 is about 145.4888311865. The cubic root of 21167 is about 27.6621821412.

Adding to 21167 its reverse (76112), we get a palindrome (97279).

Subtracting 21167 from its reverse (76112), we obtain a palindrome (54945).

The spelling of 21167 in words is "twenty-one thousand, one hundred sixty-seven".