2001201021221 has 4 divisors (see below), whose sum is σ = 2001658652172. Its totient is φ = 2000743390272.

The previous prime is 2001201021179. The next prime is 2001201021229. The reversal of 2001201021221 is 1221201021002.

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 1642985604100 + 358215417121 = 1281790^2 + 598511^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001201021221 - 2²² = 2001196826917 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001201021196 and 2001201021205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001201021229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228808916 + ... + 228817661.

It is an arithmetic number, because the mean of its divisors is an integer number (500414663043).

Almost surely, 2^{2001201021221} is an apocalyptic number.

It is an amenable number.

2001201021221 is a deficient number, since it is larger than the sum of its proper divisors (457630951).

2001201021221 is an equidigital number, since it uses as much as digits as its factorization.

2001201021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457630950.

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

Adding to 2001201021221 its reverse (1221201021002), we get a palindrome (3222402042223).

The spelling of 2001201021221 in words is "two trillion, one billion, two hundred one million, twenty-one thousand, two hundred twenty-one".