21022111221 has 4 divisors (see below), whose sum is σ = 28029481632. Its totient is φ = 14014740812.

The previous prime is 21022111217. The next prime is 21022111237. The reversal of 21022111221 is 12211122012.

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 21022111221 - 2² = 21022111217 is a prime.

It is a super-2 number, since 2×21022111221² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21022111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022161221) 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, 3503685201 + ... + 3503685206.

It is an arithmetic number, because the mean of its divisors is an integer number (7007370408).

Almost surely, 2^21022111221 is an apocalyptic number.

It is an amenable number.

21022111221 is a deficient number, since it is larger than the sum of its proper divisors (7007370411).

21022111221 is an equidigital number, since it uses as much as digits as its factorization.

21022111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7007370410.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21022111221 its reverse (12211122012), we get a palindrome (33233233233).

The spelling of 21022111221 in words is "twenty-one billion, twenty-two million, one hundred eleven thousand, two hundred twenty-one".