21112211121221 has 16 divisors (see below), whose sum is σ = 23279667660288. Its totient is φ = 18986508908400.

The previous prime is 21112211121167. The next prime is 21112211121227. The reversal of 21112211121221 is 12212111221112.

It is a happy number.

It is not a de Polignac number, because 21112211121221 - 2²² = 21112206926917 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112211121193 and 21112211121202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112211121227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8765435 + ... + 10911336.

It is an arithmetic number, because the mean of its divisors is an integer number (1454979228768).

Almost surely, 2^{21112211121221} is an apocalyptic number.

It is an amenable number.

21112211121221 is a deficient number, since it is larger than the sum of its proper divisors (2167456539067).

21112211121221 is a wasteful number, since it uses less digits than its factorization.

21112211121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19677832.

The product of its digits is 64, while the sum is 20.

Adding to 21112211121221 its reverse (12212111221112), we get a palindrome (33324322342333).

The spelling of 21112211121221 in words is "twenty-one trillion, one hundred twelve billion, two hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".