21002102020111 has 4 divisors (see below), whose sum is σ = 21020160578472. Its totient is φ = 20984043461752.

The previous prime is 21002102020093. The next prime is 21002102020139. The reversal of 21002102020111 is 11102020120012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21002102020111 - 2⁹ = 21002102019599 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002102020091 and 21002102020100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002102026111) 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 3 ways as a sum of consecutive naturals, for example, 9029277436 + ... + 9029279761.

It is an arithmetic number, because the mean of its divisors is an integer number (5255040144618).

Almost surely, 2^{21002102020111} is an apocalyptic number.

21002102020111 is a deficient number, since it is larger than the sum of its proper divisors (18058558361).

21002102020111 is a wasteful number, since it uses less digits than its factorization.

21002102020111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18058558360.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21002102020111 its reverse (11102020120012), we get a palindrome (32104122140123).

The spelling of 21002102020111 in words is "twenty-one trillion, two billion, one hundred two million, twenty thousand, one hundred eleven".