20021112121121 has 4 divisors (see below), whose sum is σ = 21198824598852. Its totient is φ = 18843399643392.

The previous prime is 20021112121111. The next prime is 20021112121151. The reversal of 20021112121121 is 12112121112002.

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 6415607739025 + 13605504382096 = 2532905^2 + 3688564^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021112121121 - 2¹⁴ = 20021112104737 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1177712477713 = 20021112121121 / (2 + 0 + 0 + 2 + 1 + 1 + 1 + 2 + 1 + 2 + 1 + 1 + 2 + 1).

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 20021112121121.

It is not an unprimeable number, because it can be changed into a prime (20021112121111) 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, 588856238840 + ... + 588856238873.

It is an arithmetic number, because the mean of its divisors is an integer number (5299706149713).

Almost surely, 2^{20021112121121} is an apocalyptic number.

It is an amenable number.

20021112121121 is a deficient number, since it is larger than the sum of its proper divisors (1177712477731).

20021112121121 is a wasteful number, since it uses less digits than its factorization.

20021112121121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1177712477730.

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

Adding to 20021112121121 its reverse (12112121112002), we get a palindrome (32133233233123).

The spelling of 20021112121121 in words is "twenty trillion, twenty-one billion, one hundred twelve million, one hundred twenty-one thousand, one hundred twenty-one".