2101011100021 has 4 divisors (see below), whose sum is σ = 2101061404044. Its totient is φ = 2100960796000.

The previous prime is 2101011099997. The next prime is 2101011100043. The reversal of 2101011100021 is 1200011101012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 765206807121 + 1335804292900 = 874761^2 + 1155770^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101011100021 - 2¹⁹ = 2101010575733 is a prime.

It is a super-2 number, since 2×2101011100021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2101011099980 and 2101011100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101011100921) 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, 25089310 + ... + 25172911.

It is an arithmetic number, because the mean of its divisors is an integer number (525265351011).

Almost surely, 2^{2101011100021} is an apocalyptic number.

It is an amenable number.

2101011100021 is a deficient number, since it is larger than the sum of its proper divisors (50304023).

2101011100021 is an equidigital number, since it uses as much as digits as its factorization.

2101011100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50304022.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 2101011100021 its reverse (1200011101012), we get a palindrome (3301022201033).

Subtracting from 2101011100021 its reverse (1200011101012), we obtain a palindrome (900999999009).

The spelling of 2101011100021 in words is "two trillion, one hundred one billion, eleven million, one hundred thousand, twenty-one".