21023223 has 16 divisors (see below), whose sum is σ = 30685536. Its totient is φ = 12723840.

The previous prime is 21023213. The next prime is 21023257. The reversal of 21023223 is 32232012.

It is not a de Polignac number, because 21023223 - 2⁴ = 21023207 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023213) 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 15 ways as a sum of consecutive naturals, for example, 2040 + ... + 6797.

It is an arithmetic number, because the mean of its divisors is an integer number (1917846).

Almost surely, 2^21023223 is an apocalyptic number.

21023223 is a deficient number, since it is larger than the sum of its proper divisors (9662313).

21023223 is a wasteful number, since it uses less digits than its factorization.

21023223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8914.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21023223 is about 4585.1088318599. The cubic root of 21023223 is about 275.9940793731.

Adding to 21023223 its reverse (32232012), we get a palindrome (53255235).

The spelling of 21023223 in words is "twenty-one million, twenty-three thousand, two hundred twenty-three".