21102001111221 has 48 divisors (see below), whose sum is σ = 29908049238144. Its totient is φ = 13188665161728.

The previous prime is 21102001111201. The next prime is 21102001111237. The reversal of 21102001111221 is 12211110020112.

It is a happy number.

It is not a de Polignac number, because 21102001111221 - 2¹¹ = 21102001109173 is a prime.

It is a super-2 number, since 2×21102001111221² (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 21102001111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102001111201) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7972042920 + ... + 7972045566.

It is an arithmetic number, because the mean of its divisors is an integer number (623084359128).

Almost surely, 2^{21102001111221} is an apocalyptic number.

It is an amenable number.

21102001111221 is a deficient number, since it is larger than the sum of its proper divisors (8806048126923).

21102001111221 is a wasteful number, since it uses less digits than its factorization.

21102001111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4478 (or 4089 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21102001111221 its reverse (12211110020112), we get a palindrome (33313111131333).

The spelling of 21102001111221 in words is "twenty-one trillion, one hundred two billion, one million, one hundred eleven thousand, two hundred twenty-one".