2001100111001 has 4 divisors (see below), whose sum is σ = 2003513984100. Its totient is φ = 1998686237904.

The previous prime is 2001100110967. The next prime is 2001100111009. The reversal of 2001100111001 is 1001110011002.

It is a happy number.

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 1111000321600 + 890099789401 = 1054040^2 + 943451^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001100111001 - 2³⁴ = 1983920241817 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2001100111001.

It is not an unprimeable number, because it can be changed into a prime (2001100111009) 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, 1206935306 + ... + 1206936963.

It is an arithmetic number, because the mean of its divisors is an integer number (500878496025).

Almost surely, 2^{2001100111001} is an apocalyptic number.

It is an amenable number.

2001100111001 is a deficient number, since it is larger than the sum of its proper divisors (2413873099).

2001100111001 is an equidigital number, since it uses as much as digits as its factorization.

2001100111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413873098.

The product of its (nonzero) digits is 2, while the sum is 8.

Adding to 2001100111001 its reverse (1001110011002), we get a palindrome (3002210122003).

Subtracting from 2001100111001 its reverse (1001110011002), we obtain a palindrome (999990099999).

It can be divided in two parts, 20011001 and 11001, that added together give a palindrome (20022002).

The spelling of 2001100111001 in words is "two trillion, one billion, one hundred million, one hundred eleven thousand, one".