21020223 has 16 divisors (see below), whose sum is σ = 32105216. Its totient is φ = 11983680.

The previous prime is 21020161. The next prime is 21020227. The reversal of 21020223 is 32202012.

It is not a de Polignac number, because 21020223 - 2⁶ = 21020159 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020199 and 21020208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11115 + ... + 12867.

It is an arithmetic number, because the mean of its divisors is an integer number (2006576).

Almost surely, 2^21020223 is an apocalyptic number.

21020223 is a deficient number, since it is larger than the sum of its proper divisors (11084993).

21020223 is a wasteful number, since it uses less digits than its factorization.

21020223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2334.

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21020223 is about 4584.7816741913. The cubic root of 21020223 is about 275.9809506911.

Adding to 21020223 its reverse (32202012), we get a palindrome (53222235).

The spelling of 21020223 in words is "twenty-one million, twenty thousand, two hundred twenty-three".