21100221101221 has 4 divisors (see below), whose sum is σ = 21116121796672. Its totient is φ = 21084320405772.

The previous prime is 21100221101207. The next prime is 21100221101269. The reversal of 21100221101221 is 12210112200112.

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 21100221101221 - 2¹¹ = 21100221099173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100221101195 and 21100221101204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100221101821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7950345735 + ... + 7950348388.

It is an arithmetic number, because the mean of its divisors is an integer number (5279030449168).

Almost surely, 2^{21100221101221} is an apocalyptic number.

It is an amenable number.

21100221101221 is a deficient number, since it is larger than the sum of its proper divisors (15900695451).

21100221101221 is a wasteful number, since it uses less digits than its factorization.

21100221101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15900695450.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21100221101221 its reverse (12210112200112), we get a palindrome (33310333301333).

The spelling of 21100221101221 in words is "twenty-one trillion, one hundred billion, two hundred twenty-one million, one hundred one thousand, two hundred twenty-one".