20021020121021 has 4 divisors (see below), whose sum is σ = 20148542542332. Its totient is φ = 19893497699712.

The previous prime is 20021020121009. The next prime is 20021020121023. The reversal of 20021020121021 is 12012102012002.

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 5396858656996 + 14624161464025 = 2323114^2 + 3824155^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021020121021 - 2¹⁴ = 20021020104637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021020120987 and 20021020121005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021020121023) 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, 63761210420 + ... + 63761210733.

It is an arithmetic number, because the mean of its divisors is an integer number (5037135635583).

Almost surely, 2^{20021020121021} is an apocalyptic number.

It is an amenable number.

20021020121021 is a deficient number, since it is larger than the sum of its proper divisors (127522421311).

20021020121021 is a wasteful number, since it uses less digits than its factorization.

20021020121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127522421310.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20021020121021 its reverse (12012102012002), we get a palindrome (32033122133023).

The spelling of 20021020121021 in words is "twenty trillion, twenty-one billion, twenty million, one hundred twenty-one thousand, twenty-one".