2001012200021 has 4 divisors (see below), whose sum is σ = 2001090362700. Its totient is φ = 2000934037344.

The previous prime is 2001012199987. The next prime is 2001012200023. The reversal of 2001012200021 is 1200022101002.

It is a happy number.

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 1164756819121 + 836255380900 = 1079239^2 + 914470^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001012200021 - 2¹⁴ = 2001012183637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2001012199975 and 2001012200011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001012200023) 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, 39042926 + ... + 39094143.

It is an arithmetic number, because the mean of its divisors is an integer number (500272590675).

Almost surely, 2^{2001012200021} is an apocalyptic number.

It is an amenable number.

2001012200021 is a deficient number, since it is larger than the sum of its proper divisors (78162679).

2001012200021 is an equidigital number, since it uses as much as digits as its factorization.

2001012200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78162678.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 2001012200021 its reverse (1200022101002), we get a palindrome (3201034301023).

The spelling of 2001012200021 in words is "two trillion, one billion, twelve million, two hundred thousand, twenty-one".