2001331101221 has 2 divisors, whose sum is σ = 2001331101222. Its totient is φ = 2001331101220.

The previous prime is 2001331101199. The next prime is 2001331101229. The reversal of 2001331101221 is 1221011331002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1853652297121 + 147678804100 = 1361489^2 + 384290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001331101221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2001331101221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001331101229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000665550610 + 1000665550611.

It is an arithmetic number, because the mean of its divisors is an integer number (1000665550611).

Almost surely, 2^{2001331101221} is an apocalyptic number.

It is an amenable number.

2001331101221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001331101221 is an equidigital number, since it uses as much as digits as its factorization.

2001331101221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 2001331101221 its reverse (1221011331002), we get a palindrome (3222342432223).

The spelling of 2001331101221 in words is "two trillion, one billion, three hundred thirty-one million, one hundred one thousand, two hundred twenty-one".