21013223 has 12 divisors (see below), whose sum is σ = 26397840. Its totient is φ = 16373280.

The previous prime is 21013217. The next prime is 21013249. The reversal of 21013223 is 32231012.

It is a happy number.

It is not a de Polignac number, because 21013223 - 2⁶ = 21013159 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21013198 and 21013207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11558 + ... + 13251.

It is an arithmetic number, because the mean of its divisors is an integer number (2199820).

Almost surely, 2^21013223 is an apocalyptic number.

21013223 is a deficient number, since it is larger than the sum of its proper divisors (5384617).

21013223 is a wasteful number, since it uses less digits than its factorization.

21013223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24838 (or 24827 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21013223 is about 4584.0182154961. The cubic root of 21013223 is about 275.9503122414.

Adding to 21013223 its reverse (32231012), we get a palindrome (53244235).

The spelling of 21013223 in words is "twenty-one million, thirteen thousand, two hundred twenty-three".