21210202220121 has 24 divisors (see below), whose sum is σ = 31380890523840. Its totient is φ = 13797441364896.

The previous prime is 21210202220117. The next prime is 21210202220131. The reversal of 21210202220121 is 12102220201212.

It is a happy number.

21210202220121 is a `hidden beast` number, since 2 + 121 + 0 + 202 + 220 + 121 = 666.

It is not a de Polignac number, because 21210202220121 - 2² = 21210202220117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210202220094 and 21210202220103.

It is not an unprimeable number, because it can be changed into a prime (21210202220131) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27099981 + ... + 27871658.

It is an arithmetic number, because the mean of its divisors is an integer number (1307537105160).

Almost surely, 2^{21210202220121} is an apocalyptic number.

It is an amenable number.

21210202220121 is a deficient number, since it is larger than the sum of its proper divisors (10170688303719).

21210202220121 is a wasteful number, since it uses less digits than its factorization.

21210202220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54972685 (or 54972682 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21210202220121 its reverse (12102220201212), we get a palindrome (33312422421333).

The spelling of 21210202220121 in words is "twenty-one trillion, two hundred ten billion, two hundred two million, two hundred twenty thousand, one hundred twenty-one".