21266 has 16 divisors (see below), whose sum is σ = 38400. Its totient is φ = 8820.

The previous prime is 21247. The next prime is 21269. The reversal of 21266 is 66212.

21266 is nontrivially palindromic in base 6.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21269) by changing a digit.

21266 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 671 + ... + 701.

It is an arithmetic number, because the mean of its divisors is an integer number (2400).

2²¹²⁶⁶ is an apocalyptic number.

21266 is a deficient number, since it is larger than the sum of its proper divisors (17134).

21266 is an equidigital number, since it uses as much as digits as its factorization.

21266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54 (or 40 counting only the distinct ones).

The product of its digits is 144, while the sum is 17.

The square root of 21266 is about 145.8286665920. The cubic root of 21266 is about 27.7052412678.

Adding to 21266 its reverse (66212), we get a palindrome (87478).

The spelling of 21266 in words is "twenty-one thousand, two hundred sixty-six".