20021211202121 has 4 divisors (see below), whose sum is σ = 20022695697792. Its totient is φ = 20019726706452.

The previous prime is 20021211202099. The next prime is 20021211202147. The reversal of 20021211202121 is 12120211212002.

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-20021211202121 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 20021211202121.

It is not an unprimeable number, because it can be changed into a prime (20021211202621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 742227605 + ... + 742254578.

It is an arithmetic number, because the mean of its divisors is an integer number (5005673924448).

Almost surely, 2^{20021211202121} is an apocalyptic number.

It is an amenable number.

20021211202121 is a deficient number, since it is larger than the sum of its proper divisors (1484495671).

20021211202121 is a wasteful number, since it uses less digits than its factorization.

20021211202121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1484495670.

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

Adding to 20021211202121 its reverse (12120211212002), we get a palindrome (32141422414123).

The spelling of 20021211202121 in words is "twenty trillion, twenty-one billion, two hundred eleven million, two hundred two thousand, one hundred twenty-one".