21100111101001 has 4 divisors (see below), whose sum is σ = 21113224906900. Its totient is φ = 21086997295104.

The previous prime is 21100111100989. The next prime is 21100111101007. The reversal of 21100111101001 is 10010111100112.

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 17584804843776 + 3515306257225 = 4193424^2 + 1874915^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100111101001 - 2⁹ = 21100111100489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100111101007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6556900536 + ... + 6556903753.

It is an arithmetic number, because the mean of its divisors is an integer number (5278306226725).

Almost surely, 2^{21100111101001} is an apocalyptic number.

It is an amenable number.

21100111101001 is a deficient number, since it is larger than the sum of its proper divisors (13113805899).

21100111101001 is a wasteful number, since it uses less digits than its factorization.

21100111101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13113805898.

The product of its (nonzero) digits is 2, while the sum is 10.

Adding to 21100111101001 its reverse (10010111100112), we get a palindrome (31110222201113).

The spelling of 21100111101001 in words is "twenty-one trillion, one hundred billion, one hundred eleven million, one hundred one thousand, one".