21221120012121 has 12 divisors (see below), whose sum is σ = 30652829581140. Its totient is φ = 14147366876160.

The previous prime is 21221120012011. The next prime is 21221120012143. The reversal of 21221120012121 is 12121002112212.

21221120012121 is a `hidden beast` number, since 212 + 211 + 200 + 1 + 21 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13499451705600 + 7721668306521 = 3674160^2 + 2778789^2 .

It is not a de Polignac number, because 21221120012121 - 2¹¹ = 21221120010073 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21221120012094 and 21221120012103.

It is not an unprimeable number, because it can be changed into a prime (21221120032121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 855960 + ... + 6570761.

It is an arithmetic number, because the mean of its divisors is an integer number (2554402465095).

Almost surely, 2^{21221120012121} is an apocalyptic number.

It is an amenable number.

21221120012121 is a deficient number, since it is larger than the sum of its proper divisors (9431709569019).

21221120012121 is a wasteful number, since it uses less digits than its factorization.

21221120012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7744216 (or 7744213 counting only the distinct ones).

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

Adding to 21221120012121 its reverse (12121002112212), we get a palindrome (33342122124333).

The spelling of 21221120012121 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty million, twelve thousand, one hundred twenty-one".