21210220121121 has 48 divisors (see below), whose sum is σ = 32106202617216. Its totient is φ = 13467388416768.

The previous prime is 21210220121119. The next prime is 21210220121231. The reversal of 21210220121121 is 12112102201212.

21210220121121 is a `hidden beast` number, since 2 + 1 + 210 + 220 + 1 + 211 + 21 = 666.

It is not a de Polignac number, because 21210220121121 - 2¹ = 21210220121119 is a prime.

It is a super-2 number, since 2×21210220121121² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21210220121094 and 21210220121103.

It is not an unprimeable number, because it can be changed into a prime (21210220521121) 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 47 ways as a sum of consecutive naturals, for example, 84909021 + ... + 85158453.

It is an arithmetic number, because the mean of its divisors is an integer number (668879221192).

Almost surely, 2^{21210220121121} is an apocalyptic number.

It is an amenable number.

21210220121121 is a deficient number, since it is larger than the sum of its proper divisors (10895982496095).

21210220121121 is a wasteful number, since it uses less digits than its factorization.

21210220121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251222 (or 251219 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21210220121121 its reverse (12112102201212), we get a palindrome (33322322322333).

The spelling of 21210220121121 in words is "twenty-one trillion, two hundred ten billion, two hundred twenty million, one hundred twenty-one thousand, one hundred twenty-one".