21002100111009 has 8 divisors (see below), whose sum is σ = 31114222386720. Its totient is φ = 14001400073988.

The previous prime is 21002100110993. The next prime is 21002100111023. The reversal of 21002100111009 is 90011100120012.

It is a happy number.

It is not a de Polignac number, because 21002100111009 - 2⁴ = 21002100110993 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002100110982 and 21002100111000.

It is not an unprimeable number, because it can be changed into a prime (21002100111029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 388927779807 + ... + 388927779860.

It is an arithmetic number, because the mean of its divisors is an integer number (3889277798340).

Almost surely, 2^{21002100111009} is an apocalyptic number.

It is an amenable number.

21002100111009 is a deficient number, since it is larger than the sum of its proper divisors (10112122275711).

21002100111009 is an equidigital number, since it uses as much as digits as its factorization.

21002100111009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777855559676 (or 777855559670 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 18.

The spelling of 21002100111009 in words is "twenty-one trillion, two billion, one hundred million, one hundred eleven thousand, nine".