21229 has 8 divisors (see below), whose sum is σ = 24192. Its totient is φ = 18480.

The previous prime is 21227. The next prime is 21247. The reversal of 21229 is 92212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21229 - 2¹ = 21227 is a prime.

It is a Duffinian number.

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 (21221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 264 + ... + 334.

It is an arithmetic number, because the mean of its divisors is an integer number (3024).

2²¹²²⁹ is an apocalyptic number.

It is an amenable number.

21229 is a deficient number, since it is larger than the sum of its proper divisors (2963).

21229 is a wasteful number, since it uses less digits than its factorization.

21229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107.

The product of its digits is 72, while the sum is 16.

The square root of 21229 is about 145.7017501611. The cubic root of 21229 is about 27.6891641335.

The spelling of 21229 in words is "twenty-one thousand, two hundred twenty-nine".