1001122221221 has 4 divisors (see below), whose sum is σ = 1001126544972. Its totient is φ = 1001117897472.

The previous prime is 1001122221217. The next prime is 1001122221223. The reversal of 1001122221221 is 1221222211001.

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 576916202500 + 424206018721 = 759550^2 + 651311^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001122221221 - 2² = 1001122221217 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 1001122221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001122221223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1793660 + ... + 2284613.

It is an arithmetic number, because the mean of its divisors is an integer number (250281636243).

Almost surely, 2^{1001122221221} is an apocalyptic number.

It is an amenable number.

1001122221221 is a deficient number, since it is larger than the sum of its proper divisors (4323751).

1001122221221 is an equidigital number, since it uses as much as digits as its factorization.

1001122221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4323750.

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

Adding to 1001122221221 its reverse (1221222211001), we get a palindrome (2222344432222).

The spelling of 1001122221221 in words is "one trillion, one billion, one hundred twenty-two million, two hundred twenty-one thousand, two hundred twenty-one".