21101102021221 has 8 divisors (see below), whose sum is σ = 21308852199960. Its totient is φ = 20893720522752.

The previous prime is 21101102021173. The next prime is 21101102021243. The reversal of 21101102021221 is 12212020110112.

It can be written as a sum of positive squares in 4 ways, for example, as 5438741716321 + 15662360304900 = 2332111^2 + 3957570^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21101102021221 - 2⁴³ = 12305008999013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101102021195 and 21101102021204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101102021261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92055036 + ... + 92283973.

It is an arithmetic number, because the mean of its divisors is an integer number (2663606524995).

Almost surely, 2^{21101102021221} is an apocalyptic number.

It is an amenable number.

21101102021221 is a deficient number, since it is larger than the sum of its proper divisors (207750178739).

21101102021221 is a wasteful number, since it uses less digits than its factorization.

21101102021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184340135.

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

Adding to 21101102021221 its reverse (12212020110112), we get a palindrome (33313122131333).

The spelling of 21101102021221 in words is "twenty-one trillion, one hundred one billion, one hundred two million, twenty-one thousand, two hundred twenty-one".