21020121012121 has 16 divisors (see below), whose sum is σ = 26466378427008. Its totient is φ = 16217143632000.

The previous prime is 21020121012119. The next prime is 21020121012139. The reversal of 21020121012121 is 12121012102012.

It is a cyclic number.

It is not a de Polignac number, because 21020121012121 - 2¹ = 21020121012119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020121012095 and 21020121012104.

It is not an unprimeable number, because it can be changed into a prime (21020121012221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1351420860 + ... + 1351436413.

It is an arithmetic number, because the mean of its divisors is an integer number (1654148651688).

Almost surely, 2^{21020121012121} is an apocalyptic number.

It is an amenable number.

21020121012121 is a deficient number, since it is larger than the sum of its proper divisors (5446257414887).

21020121012121 is a wasteful number, since it uses less digits than its factorization.

21020121012121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2702857392.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21020121012121 its reverse (12121012102012), we get a palindrome (33141133114133).

The spelling of 21020121012121 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, twelve thousand, one hundred twenty-one".