21221111333 has 4 divisors (see below), whose sum is σ = 21221664288. Its totient is φ = 21220558380.

The previous prime is 21221111291. The next prime is 21221111363. The reversal of 21221111333 is 33311112212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21221111333 - 2²⁰ = 21220062757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221111363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214241 + ... + 297222.

It is an arithmetic number, because the mean of its divisors is an integer number (5305416072).

Almost surely, 2^21221111333 is an apocalyptic number.

It is an amenable number.

21221111333 is a deficient number, since it is larger than the sum of its proper divisors (552955).

21221111333 is an equidigital number, since it uses as much as digits as its factorization.

21221111333 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552954.

The product of its digits is 216, while the sum is 20.

Adding to 21221111333 its reverse (33311112212), we get a palindrome (54532223545).

The spelling of 21221111333 in words is "twenty-one billion, two hundred twenty-one million, one hundred eleven thousand, three hundred thirty-three".