21101101221 has 16 divisors (see below), whose sum is σ = 29089152000. Its totient is φ = 13595329728.

The previous prime is 21101101201. The next prime is 21101101223. The reversal of 21101101221 is 12210110112.

It is not a de Polignac number, because 21101101221 - 2¹⁵ = 21101068453 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21101101197 and 21101101206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101101223) 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, 621381 + ... + 654458.

It is an arithmetic number, because the mean of its divisors is an integer number (1818072000).

Almost surely, 2^21101101221 is an apocalyptic number.

It is an amenable number.

21101101221 is a deficient number, since it is larger than the sum of its proper divisors (7988050779).

21101101221 is a wasteful number, since it uses less digits than its factorization.

21101101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276028.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21101101221 its reverse (12210110112), we get a palindrome (33311211333).

The spelling of 21101101221 in words is "twenty-one billion, one hundred one million, one hundred one thousand, two hundred twenty-one".