21100001122221 has 16 divisors (see below), whose sum is σ = 33189556297728. Its totient is φ = 11668203385200.

The previous prime is 21100001122171. The next prime is 21100001122247. The reversal of 21100001122221 is 12222110000112.

It is not a de Polignac number, because 21100001122221 - 2⁹ = 21100001121709 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21100001122221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100001122721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16205837385 + ... + 16205838686.

It is an arithmetic number, because the mean of its divisors is an integer number (2074347268608).

Almost surely, 2^{21100001122221} is an apocalyptic number.

21100001122221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21100001122221 is a deficient number, since it is larger than the sum of its proper divisors (12089555175507).

21100001122221 is a wasteful number, since it uses less digits than its factorization.

21100001122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32411676112.

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

Adding to 21100001122221 its reverse (12222110000112), we get a palindrome (33322111122333).

The spelling of 21100001122221 in words is "twenty-one trillion, one hundred billion, one million, one hundred twenty-two thousand, two hundred twenty-one".