1001122122221 has 4 divisors (see below), whose sum is σ = 1078131516252. Its totient is φ = 924112728192.

The previous prime is 1001122122211. The next prime is 1001122122241. The reversal of 1001122122221 is 1222212211001.

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 374825572900 + 626296549321 = 612230^2 + 791389^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001122122221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1001122122221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001122122211) 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, 38504696996 + ... + 38504697021.

It is an arithmetic number, because the mean of its divisors is an integer number (269532879063).

Almost surely, 2^{1001122122221} is an apocalyptic number.

It is an amenable number.

1001122122221 is a deficient number, since it is larger than the sum of its proper divisors (77009394031).

1001122122221 is an equidigital number, since it uses as much as digits as its factorization.

1001122122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77009394030.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1001122122221 its reverse (1222212211001), we get a palindrome (2223334333222).

The spelling of 1001122122221 in words is "one trillion, one billion, one hundred twenty-two million, one hundred twenty-two thousand, two hundred twenty-one".