21221223 has 4 divisors (see below), whose sum is σ = 28294968. Its totient is φ = 14147480.

The previous prime is 21221171. The next prime is 21221237. The reversal of 21221223 is 32212212.

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 21221223 - 2⁹ = 21220711 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221273) 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, 3536868 + ... + 3536873.

It is an arithmetic number, because the mean of its divisors is an integer number (7073742).

Almost surely, 2^21221223 is an apocalyptic number.

21221223 is a deficient number, since it is larger than the sum of its proper divisors (7073745).

21221223 is an equidigital number, since it uses as much as digits as its factorization.

21221223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7073744.

The product of its digits is 96, while the sum is 15.

The square root of 21221223 is about 4606.6498673114. The cubic root of 21221223 is about 276.8578251826.

Adding to 21221223 its reverse (32212212), we get a palindrome (53433435).

The spelling of 21221223 in words is "twenty-one million, two hundred twenty-one thousand, two hundred twenty-three".