202121122121 has 4 divisors (see below), whose sum is σ = 202122783744. Its totient is φ = 202119460500.

The previous prime is 202121122109. The next prime is 202121122127. The reversal of 202121122121 is 121221121202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-202121122121 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 202121122121.

It is not an unprimeable number, because it can be changed into a prime (202121122127) 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, 632585 + ... + 896886.

It is an arithmetic number, because the mean of its divisors is an integer number (50530695936).

Almost surely, 2^202121122121 is an apocalyptic number.

It is an amenable number.

202121122121 is a deficient number, since it is larger than the sum of its proper divisors (1661623).

202121122121 is a wasteful number, since it uses less digits than its factorization.

202121122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1661622.

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

Adding to 202121122121 its reverse (121221121202), we get a palindrome (323342243323).

The spelling of 202121122121 in words is "two hundred two billion, one hundred twenty-one million, one hundred twenty-two thousand, one hundred twenty-one".