21020121112111 has 24 divisors (see below), whose sum is σ = 23334955282800. Its totient is φ = 18918838224000.

The previous prime is 21020121112091. The next prime is 21020121112157. The reversal of 21020121112111 is 11121112102012.

It is a de Polignac number, because none of the positive numbers 2^k-21020121112111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020121118111) 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, 245464860 + ... + 245550478.

It is an arithmetic number, because the mean of its divisors is an integer number (972289803450).

Almost surely, 2^{21020121112111} is an apocalyptic number.

21020121112111 is a deficient number, since it is larger than the sum of its proper divisors (2314834170689).

21020121112111 is a wasteful number, since it uses less digits than its factorization.

21020121112111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105831 (or 105820 counting only the distinct ones).

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

Adding to 21020121112111 its reverse (11121112102012), we get a palindrome (32141233214123).

It can be divided in two parts, 2102012 and 1112111, that added together give a palindrome (3214123).

The spelling of 21020121112111 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, one hundred twelve thousand, one hundred eleven".