21121112112221 has 8 divisors (see below), whose sum is σ = 23045767773600. Its totient is φ = 19197215544240.

The previous prime is 21121112112179. The next prime is 21121112112253. The reversal of 21121112112221 is 12221121112112.

It is a happy number.

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 21121112112221 - 2¹⁸ = 21121111850077 is a prime.

It is a super-2 number, since 2×21121112112221² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121112112193 and 21121112112202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121112112721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189715166 + ... + 189826463.

It is an arithmetic number, because the mean of its divisors is an integer number (2880720971700).

Almost surely, 2^{21121112112221} is an apocalyptic number.

It is an amenable number.

21121112112221 is a deficient number, since it is larger than the sum of its proper divisors (1924655661379).

21121112112221 is a wasteful number, since it uses less digits than its factorization.

21121112112221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379546699.

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

Adding to 21121112112221 its reverse (12221121112112), we get a palindrome (33342233224333).

The spelling of 21121112112221 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred twelve million, one hundred twelve thousand, two hundred twenty-one".