21001111110021 has 8 divisors (see below), whose sum is σ = 32001693120064. Its totient is φ = 12000634920000.

The previous prime is 21001111109987. The next prime is 21001111110059. The reversal of 21001111110021 is 12001111110012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21001111110021 - 2⁹ = 21001111109509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001111109979 and 21001111110006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001111110521) 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 7 ways as a sum of consecutive naturals, for example, 500026454980 + ... + 500026455021.

It is an arithmetic number, because the mean of its divisors is an integer number (4000211640008).

Almost surely, 2^{21001111110021} is an apocalyptic number.

21001111110021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21001111110021 is a deficient number, since it is larger than the sum of its proper divisors (11000582010043).

21001111110021 is a wasteful number, since it uses less digits than its factorization.

21001111110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000052910011.

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 21001111110021 its reverse (12001111110012), we get a palindrome (33002222220033).

Subtracting from 21001111110021 its reverse (12001111110012), we obtain a palindrome (9000000000009).

The spelling of 21001111110021 in words is "twenty-one trillion, one billion, one hundred eleven million, one hundred ten thousand, twenty-one".