2100111200021 has 4 divisors (see below), whose sum is σ = 2100680185344. Its totient is φ = 2099542214700.

The previous prime is 2100111200017. The next prime is 2100111200041. The reversal of 2100111200021 is 1200021110012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2100111200021 - 2² = 2100111200017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2100111199975 and 2100111200011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2100111200041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 284487125 + ... + 284494506.

It is an arithmetic number, because the mean of its divisors is an integer number (525170046336).

Almost surely, 2^{2100111200021} is an apocalyptic number.

It is an amenable number.

2100111200021 is a deficient number, since it is larger than the sum of its proper divisors (568985323).

2100111200021 is an equidigital number, since it uses as much as digits as its factorization.

2100111200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568985322.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 2100111200021 its reverse (1200021110012), we get a palindrome (3300132310033).

Subtracting from 2100111200021 its reverse (1200021110012), we obtain a palindrome (900090090009).

The spelling of 2100111200021 in words is "two trillion, one hundred billion, one hundred eleven million, two hundred thousand, twenty-one".