21111020121021 has 32 divisors (see below), whose sum is σ = 30464174254080. Its totient is φ = 12960073353600.

The previous prime is 21111020121019. The next prime is 21111020121049. The reversal of 21111020121021 is 12012102011112.

It is a happy number.

It is not a de Polignac number, because 21111020121021 - 2¹ = 21111020121019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111020141021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16033435 + ... + 17300088.

It is an arithmetic number, because the mean of its divisors is an integer number (952005445440).

Almost surely, 2^{21111020121021} is an apocalyptic number.

It is an amenable number.

21111020121021 is a deficient number, since it is larger than the sum of its proper divisors (9353154133059).

21111020121021 is a wasteful number, since it uses less digits than its factorization.

21111020121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33333857.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21111020121021 its reverse (12012102011112), we get a palindrome (33123122132133).

The spelling of 21111020121021 in words is "twenty-one trillion, one hundred eleven billion, twenty million, one hundred twenty-one thousand, twenty-one".