21234223 has 4 divisors (see below), whose sum is σ = 21260848. Its totient is φ = 21207600.

The previous prime is 21234211. The next prime is 21234281. The reversal of 21234223 is 32243212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21234223 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 21234223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234203) 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, 12078 + ... + 13723.

It is an arithmetic number, because the mean of its divisors is an integer number (5315212).

Almost surely, 2^21234223 is an apocalyptic number.

21234223 is a deficient number, since it is larger than the sum of its proper divisors (26625).

21234223 is an equidigital number, since it uses as much as digits as its factorization.

21234223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26624.

The product of its digits is 576, while the sum is 19.

The square root of 21234223 is about 4608.0606549827. The cubic root of 21234223 is about 276.9143474832.

Adding to 21234223 its reverse (32243212), we get a palindrome (53477435).

The spelling of 21234223 in words is "twenty-one million, two hundred thirty-four thousand, two hundred twenty-three".