21100121212111 has 4 divisors (see below), whose sum is σ = 21141575281800. Its totient is φ = 21058667142424.

The previous prime is 21100121212057. The next prime is 21100121212139. The reversal of 21100121212111 is 11121212100112.

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 21100121212111 - 2¹⁹ = 21100120687823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100121212151) 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, 20727034081 + ... + 20727035098.

It is an arithmetic number, because the mean of its divisors is an integer number (5285393820450).

Almost surely, 2^{21100121212111} is an apocalyptic number.

21100121212111 is a deficient number, since it is larger than the sum of its proper divisors (41454069689).

21100121212111 is an equidigital number, since it uses as much as digits as its factorization.

21100121212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41454069688.

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 21100121212111 its reverse (11121212100112), we get a palindrome (32221333312223).

The spelling of 21100121212111 in words is "twenty-one trillion, one hundred billion, one hundred twenty-one million, two hundred twelve thousand, one hundred eleven".