21002200111221 has 64 divisors (see below), whose sum is σ = 32905791744000. Its totient is φ = 11663590982400.

The previous prime is 21002200111169. The next prime is 21002200111283. The reversal of 21002200111221 is 12211100220012.

It is a de Polignac number, because none of the positive numbers 2^k-21002200111221 is a prime.

It is a super-2 number, since 2×21002200111221² (a number of 27 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 21002200111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002200111021) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4515628746 + ... + 4515633396.

It is an arithmetic number, because the mean of its divisors is an integer number (514152996000).

Almost surely, 2^{21002200111221} is an apocalyptic number.

21002200111221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21002200111221 is a deficient number, since it is larger than the sum of its proper divisors (11903591632779).

21002200111221 is a wasteful number, since it uses less digits than its factorization.

21002200111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10074.

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

Adding to 21002200111221 its reverse (12211100220012), we get a palindrome (33213300331233).

The spelling of 21002200111221 in words is "twenty-one trillion, two billion, two hundred million, one hundred eleven thousand, two hundred twenty-one".