21100122100121 has 4 divisors (see below), whose sum is σ = 21103381819572. Its totient is φ = 21096862380672.

The previous prime is 21100122100111. The next prime is 21100122100139. The reversal of 21100122100121 is 12100122100112.

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 3338440579600 + 17761681520521 = 1827140^2 + 4214461^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100122100121 - 2¹⁰ = 21100122099097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100122100096 and 21100122100105.

It is not an unprimeable number, because it can be changed into a prime (21100122100111) 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, 1629850016 + ... + 1629862961.

It is an arithmetic number, because the mean of its divisors is an integer number (5275845454893).

Almost surely, 2^{21100122100121} is an apocalyptic number.

It is an amenable number.

21100122100121 is a deficient number, since it is larger than the sum of its proper divisors (3259719451).

21100122100121 is an equidigital number, since it uses as much as digits as its factorization.

21100122100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3259719450.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21100122100121 its reverse (12100122100112), we get a palindrome (33200244200233).

Subtracting from 21100122100121 its reverse (12100122100112), we obtain a palindrome (9000000000009).

It can be divided in two parts, 21100 and 122100121, that added together give a palindrome (122121221).

The spelling of 21100122100121 in words is "twenty-one trillion, one hundred billion, one hundred twenty-two million, one hundred thousand, one hundred twenty-one".