21223203021 has 12 divisors (see below), whose sum is σ = 31158291580. Its totient is φ = 13916854080.

The previous prime is 21223203013. The next prime is 21223203047. The reversal of 21223203021 is 12030232212.

21223203021 is a `hidden beast` number, since 21 + 22 + 320 + 302 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1062042921 + 20161160100 = 32589^2 + 141990^2 .

It is not a de Polignac number, because 21223203021 - 2³ = 21223203013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21223202985 and 21223203003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223205021) 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 11 ways as a sum of consecutive naturals, for example, 19328416 + ... + 19329513.

Almost surely, 2^21223203021 is an apocalyptic number.

It is an amenable number.

21223203021 is a deficient number, since it is larger than the sum of its proper divisors (9935088559).

21223203021 is a wasteful number, since it uses less digits than its factorization.

21223203021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38657996 (or 38657993 counting only the distinct ones).

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

Adding to 21223203021 its reverse (12030232212), we get a palindrome (33253435233).

The spelling of 21223203021 in words is "twenty-one billion, two hundred twenty-three million, two hundred three thousand, twenty-one".