21102002122121 has 4 divisors (see below), whose sum is σ = 21107741043972. Its totient is φ = 21096263200272.

The previous prime is 21102002122099. The next prime is 21102002122247. The reversal of 21102002122121 is 12122120020112.

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 6065561162896 + 15036440959225 = 2462836^2 + 3877685^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102002122121 - 2⁶ = 21102002122057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21102002122121.

It is not an unprimeable number, because it can be changed into a prime (21102002022121) 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, 2869455410 + ... + 2869462763.

It is an arithmetic number, because the mean of its divisors is an integer number (5276935260993).

Almost surely, 2^{21102002122121} is an apocalyptic number.

It is an amenable number.

21102002122121 is a deficient number, since it is larger than the sum of its proper divisors (5738921851).

21102002122121 is an equidigital number, since it uses as much as digits as its factorization.

21102002122121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5738921850.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21102002122121 its reverse (12122120020112), we get a palindrome (33224122142233).

The spelling of 21102002122121 in words is "twenty-one trillion, one hundred two billion, two million, one hundred twenty-two thousand, one hundred twenty-one".