21100211111221 has 16 divisors (see below), whose sum is σ = 23139395032320. Its totient is φ = 19081362343680.

The previous prime is 21100211111209. The next prime is 21100211111263. The reversal of 21100211111221 is 12211111200112.

It is a cyclic number.

It is not a de Polignac number, because 21100211111221 - 2³⁷ = 20962772157749 is a prime.

It is a super-2 number, since 2×21100211111221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100211111195 and 21100211111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100211111621) 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, 1819416 + ... + 6746161.

It is an arithmetic number, because the mean of its divisors is an integer number (1446212189520).

Almost surely, 2^{21100211111221} is an apocalyptic number.

It is an amenable number.

21100211111221 is a deficient number, since it is larger than the sum of its proper divisors (2039183921099).

21100211111221 is a wasteful number, since it uses less digits than its factorization.

21100211111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8566764.

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

Adding to 21100211111221 its reverse (12211111200112), we get a palindrome (33311322311333).

The spelling of 21100211111221 in words is "twenty-one trillion, one hundred billion, two hundred eleven million, one hundred eleven thousand, two hundred twenty-one".