21121100020221 has 64 divisors (see below), whose sum is σ = 29343192883200. Its totient is φ = 13504242240000.

The previous prime is 21121100020183. The next prime is 21121100020291. The reversal of 21121100020221 is 12202000112112.

It is not a de Polignac number, because 21121100020221 - 2⁶ = 21121100020157 is a prime.

It is a super-2 number, since 2×21121100020221² (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 21121100020221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121100020291) 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, 749945086 + ... + 749973248.

It is an arithmetic number, because the mean of its divisors is an integer number (458487388800).

Almost surely, 2^{21121100020221} is an apocalyptic number.

It is an amenable number.

21121100020221 is a deficient number, since it is larger than the sum of its proper divisors (8222092862979).

21121100020221 is a wasteful number, since it uses less digits than its factorization.

21121100020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28778.

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

Adding to 21121100020221 its reverse (12202000112112), we get a palindrome (33323100132333).

The spelling of 21121100020221 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred million, twenty thousand, two hundred twenty-one".