21026223 has 10 divisors (see below), whose sum is σ = 31409664. Its totient is φ = 14017428.

The previous prime is 21026197. The next prime is 21026231. The reversal of 21026223 is 32262012.

It is not a de Polignac number, because 21026223 - 2⁵ = 21026191 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21026196 and 21026205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 129711 + ... + 129872.

Almost surely, 2^21026223 is an apocalyptic number.

21026223 is a deficient number, since it is larger than the sum of its proper divisors (10383441).

21026223 is an equidigital number, since it uses as much as digits as its factorization.

21026223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259595 (or 259586 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21026223 is about 4585.4359661869. The cubic root of 21026223 is about 276.0072068061.

Adding to 21026223 its reverse (32262012), we get a palindrome (53288235).

The spelling of 21026223 in words is "twenty-one million, twenty-six thousand, two hundred twenty-three".