1001211122221 has 2 divisors, whose sum is σ = 1001211122222. Its totient is φ = 1001211122220.

The previous prime is 1001211122209. The next prime is 1001211122231. The reversal of 1001211122221 is 1222211121001.

1001211122221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 530004384196 + 471206738025 = 728014^2 + 686445^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001211122221 is a prime.

It is a super-2 number, since 2×1001211122221² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1001211122195 and 1001211122204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001211122231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500605561110 + 500605561111.

It is an arithmetic number, because the mean of its divisors is an integer number (500605561111).

Almost surely, 2^{1001211122221} is an apocalyptic number.

It is an amenable number.

1001211122221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001211122221 is an equidigital number, since it uses as much as digits as its factorization.

1001211122221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1001211122221 its reverse (1222211121001), we get a palindrome (2223422243222).

The spelling of 1001211122221 in words is "one trillion, one billion, two hundred eleven million, one hundred twenty-two thousand, two hundred twenty-one".