21002100111211 has 4 divisors (see below), whose sum is σ = 21002119097112. Its totient is φ = 21002081125312.

The previous prime is 21002100111193. The next prime is 21002100111301. The reversal of 21002100111211 is 11211100120012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21002100111211 - 2¹¹ = 21002100109163 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002100111191 and 21002100111200.

It is not an unprimeable number, because it can be changed into a prime (21002100111911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7723750 + ... + 10082683.

It is an arithmetic number, because the mean of its divisors is an integer number (5250529774278).

Almost surely, 2^{21002100111211} is an apocalyptic number.

21002100111211 is a deficient number, since it is larger than the sum of its proper divisors (18985901).

21002100111211 is a wasteful number, since it uses less digits than its factorization.

21002100111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18985900.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21002100111211 its reverse (11211100120012), we get a palindrome (32213200231223).

The spelling of 21002100111211 in words is "twenty-one trillion, two billion, one hundred million, one hundred eleven thousand, two hundred eleven".