21100111121221 has 8 divisors (see below), whose sum is σ = 23044253788224. Its totient is φ = 19160293578720.

The previous prime is 21100111121213. The next prime is 21100111121231. The reversal of 21100111121221 is 12212111100112.

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 21100111121221 - 2³ = 21100111121213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100111121195 and 21100111121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100111121231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1081270920 + ... + 1081290433.

It is an arithmetic number, because the mean of its divisors is an integer number (2880531723528).

Almost surely, 2^{21100111121221} is an apocalyptic number.

It is an amenable number.

21100111121221 is a deficient number, since it is larger than the sum of its proper divisors (1944142667003).

21100111121221 is a wasteful number, since it uses less digits than its factorization.

21100111121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2162562251.

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

Adding to 21100111121221 its reverse (12212111100112), we get a palindrome (33312222221333).

The spelling of 21100111121221 in words is "twenty-one trillion, one hundred billion, one hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".