21002101110021 has 32 divisors (see below), whose sum is σ = 28819905269760. Its totient is φ = 13596649524864.

The previous prime is 21002101110007. The next prime is 21002101110037. The reversal of 21002101110021 is 12001110120012.

It is not a de Polignac number, because 21002101110021 - 2²⁷ = 21001966892293 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002101109979 and 21002101110006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002101110061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 117975340 + ... + 118153226.

It is an arithmetic number, because the mean of its divisors is an integer number (900622039680).

Almost surely, 2^{21002101110021} is an apocalyptic number.

It is an amenable number.

21002101110021 is a deficient number, since it is larger than the sum of its proper divisors (7817804159739).

21002101110021 is a wasteful number, since it uses less digits than its factorization.

21002101110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183225.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21002101110021 its reverse (12001110120012), we get a palindrome (33003211230033).

Subtracting from 21002101110021 its reverse (12001110120012), we obtain a palindrome (9000990990009).

The spelling of 21002101110021 in words is "twenty-one trillion, two billion, one hundred one million, one hundred ten thousand, twenty-one".