20201221101001 has 4 divisors (see below), whose sum is σ = 20897814932100. Its totient is φ = 19504627269904.

The previous prime is 20201221100993. The next prime is 20201221101143. The reversal of 20201221101001 is 10010112210202.

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 5505874531600 + 14695346569401 = 2346460^2 + 3833451^2 .

It is a cyclic number.

It is not a de Polignac number, because 20201221101001 - 2³ = 20201221100993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20201221101401) 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, 348296915506 + ... + 348296915563.

It is an arithmetic number, because the mean of its divisors is an integer number (5224453733025).

Almost surely, 2^{20201221101001} is an apocalyptic number.

It is an amenable number.

20201221101001 is a deficient number, since it is larger than the sum of its proper divisors (696593831099).

20201221101001 is an equidigital number, since it uses as much as digits as its factorization.

20201221101001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696593831098.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20201221101001 its reverse (10010112210202), we get a palindrome (30211333311203).

The spelling of 20201221101001 in words is "twenty trillion, two hundred one billion, two hundred twenty-one million, one hundred one thousand, one".