21320333221 has 12 divisors (see below), whose sum is σ = 23439587500. Its totient is φ = 19378117440.

The previous prime is 21320333213. The next prime is 21320333269. The reversal of 21320333221 is 12233302312.

It can be written as a sum of positive squares in 2 ways, for example, as 380796196 + 20939537025 = 19514^2 + 144705^2 .

It is not a de Polignac number, because 21320333221 - 2³ = 21320333213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21320333192 and 21320333201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320333291) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 680305 + ... + 710953.

Almost surely, 2^21320333221 is an apocalyptic number.

It is an amenable number.

21320333221 is a deficient number, since it is larger than the sum of its proper divisors (2119254279).

21320333221 is a wasteful number, since it uses less digits than its factorization.

21320333221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36420 (or 36409 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 22.

Adding to 21320333221 its reverse (12233302312), we get a palindrome (33553635533).

The spelling of 21320333221 in words is "twenty-one billion, three hundred twenty million, three hundred thirty-three thousand, two hundred twenty-one".