2121202012121 has 4 divisors (see below), whose sum is σ = 2121228683700. Its totient is φ = 2121175340544.

The previous prime is 2121202012117. The next prime is 2121202012183. The reversal of 2121202012121 is 1212102021212.

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 1864521975625 + 256680036496 = 1365475^2 + 506636^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121202012121 - 2² = 2121202012117 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 2121202012121.

It is not an unprimeable number, because it can be changed into a prime (2121207012121) 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, 13216136 + ... + 13375673.

It is an arithmetic number, because the mean of its divisors is an integer number (530307170925).

Almost surely, 2^{2121202012121} is an apocalyptic number.

It is an amenable number.

2121202012121 is a deficient number, since it is larger than the sum of its proper divisors (26671579).

2121202012121 is an equidigital number, since it uses as much as digits as its factorization.

2121202012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26671578.

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

Adding to 2121202012121 its reverse (1212102021212), we get a palindrome (3333304033333).

Subtracting from 2121202012121 its reverse (1212102021212), we obtain a palindrome (909099990909).

The spelling of 2121202012121 in words is "two trillion, one hundred twenty-one billion, two hundred two million, twelve thousand, one hundred twenty-one".