21201102112121 has 4 divisors (see below), whose sum is σ = 21277640387172. Its totient is φ = 21124563837072.

The previous prime is 21201102112111. The next prime is 21201102112133. The reversal of 21201102112121 is 12121120110212.

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 1228470756496 + 19972631355625 = 1108364^2 + 4469075^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201102112121 - 2³⁸ = 20926224205177 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201102112121.

It is not an unprimeable number, because it can be changed into a prime (21201102112111) 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, 38269137110 + ... + 38269137663.

It is an arithmetic number, because the mean of its divisors is an integer number (5319410096793).

Almost surely, 2^{21201102112121} is an apocalyptic number.

It is an amenable number.

21201102112121 is a deficient number, since it is larger than the sum of its proper divisors (76538275051).

21201102112121 is an equidigital number, since it uses as much as digits as its factorization.

21201102112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76538275050.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21201102112121 its reverse (12121120110212), we get a palindrome (33322222222333).

The spelling of 21201102112121 in words is "twenty-one trillion, two hundred one billion, one hundred two million, one hundred twelve thousand, one hundred twenty-one".