21126223 has 8 divisors (see below), whose sum is σ = 22974192. Its totient is φ = 19345536.

The previous prime is 21126169. The next prime is 21126229. The reversal of 21126223 is 32262112.

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 21126223 - 2⁹ = 21125711 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21126223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126229) 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, 16165 + ... + 17422.

It is an arithmetic number, because the mean of its divisors is an integer number (2871774).

Almost surely, 2^21126223 is an apocalyptic number.

21126223 is a deficient number, since it is larger than the sum of its proper divisors (1847969).

21126223 is a wasteful number, since it uses less digits than its factorization.

21126223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33641.

The product of its digits is 288, while the sum is 19.

The square root of 21126223 is about 4596.3271206475. The cubic root of 21126223 is about 276.4440752489. Note that the first 3 decimals are identical.

Adding to 21126223 its reverse (32262112), we get a palindrome (53388335).

The spelling of 21126223 in words is "twenty-one million, one hundred twenty-six thousand, two hundred twenty-three".