21120100111021 has 32 divisors (see below), whose sum is σ = 21925795989600. Its totient is φ = 20333796249600.

The previous prime is 21120100111001. The next prime is 21120100111067. The reversal of 21120100111021 is 12011100102112.

It is a happy number.

It can be written as a sum of positive squares in 16 ways, for example, as 5511390093225 + 15608710017796 = 2347635^2 + 3950786^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120100111021 - 2²¹ = 21120098013869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120100110992 and 21120100111010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120100111001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 783576481 + ... + 783603433.

It is an arithmetic number, because the mean of its divisors is an integer number (685181124675).

Almost surely, 2^{21120100111021} is an apocalyptic number.

It is an amenable number.

21120100111021 is a deficient number, since it is larger than the sum of its proper divisors (805695878579).

21120100111021 is a wasteful number, since it uses less digits than its factorization.

21120100111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28417.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21120100111021 its reverse (12011100102112), we get a palindrome (33131200213133).

The spelling of 21120100111021 in words is "twenty-one trillion, one hundred twenty billion, one hundred million, one hundred eleven thousand, twenty-one".