21333333221 has 16 divisors (see below), whose sum is σ = 22862459520. Its totient is φ = 19861195200.

The previous prime is 21333333199. The next prime is 21333333227. The reversal of 21333333221 is 12233333312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21333333221 - 2¹⁰ = 21333332197 is a prime.

It is a super-2 number, since 2×21333333221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21333333227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59231 + ... + 214883.

It is an arithmetic number, because the mean of its divisors is an integer number (1428903720).

Almost surely, 2^21333333221 is an apocalyptic number.

It is an amenable number.

21333333221 is a deficient number, since it is larger than the sum of its proper divisors (1529126299).

21333333221 is a wasteful number, since it uses less digits than its factorization.

21333333221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155836.

The product of its digits is 5832, while the sum is 26.

Adding to 21333333221 its reverse (12233333312), we get a palindrome (33566666533).

Subtracting from 21333333221 its reverse (12233333312), we obtain a palindrome (9099999909).

The spelling of 21333333221 in words is "twenty-one billion, three hundred thirty-three million, three hundred thirty-three thousand, two hundred twenty-one".