20201221002001 has 8 divisors (see below), whose sum is σ = 21755304983720. Its totient is φ = 18647157578112.

The previous prime is 20201221001999. The next prime is 20201221002049. The reversal of 20201221002001 is 10020012210202.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1736797151376 + 18464423850625 = 1317876^2 + 4297025^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20201221002001 - 2¹ = 20201221001999 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20201221002601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3067620 + ... + 7057813.

It is an arithmetic number, because the mean of its divisors is an integer number (2719413122965).

Almost surely, 2^{20201221002001} is an apocalyptic number.

It is an amenable number.

20201221002001 is a deficient number, since it is larger than the sum of its proper divisors (1554083981719).

20201221002001 is a wasteful number, since it uses less digits than its factorization.

20201221002001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10278915.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20201221002001 its reverse (10020012210202), we get a palindrome (30221233212203).

The spelling of 20201221002001 in words is "twenty trillion, two hundred one billion, two hundred twenty-one million, two thousand, one".