1001011220021 has 4 divisors (see below), whose sum is σ = 1001226172332. Its totient is φ = 1000796267712.

The previous prime is 1001011219921. The next prime is 1001011220039. The reversal of 1001011220021 is 1200221101001.

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 482483052100 + 518528167921 = 694610^2 + 720089^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001011220021 - 2¹⁰ = 1001011218997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1001011219984 and 1001011220011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001011220071) 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, 107469170 + ... + 107478483.

It is an arithmetic number, because the mean of its divisors is an integer number (250306543083).

Almost surely, 2^{1001011220021} is an apocalyptic number.

It is an amenable number.

1001011220021 is a deficient number, since it is larger than the sum of its proper divisors (214952311).

1001011220021 is an equidigital number, since it uses as much as digits as its factorization.

1001011220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214952310.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1001011220021 its reverse (1200221101001), we get a palindrome (2201232321022).

The spelling of 1001011220021 in words is "one trillion, one billion, eleven million, two hundred twenty thousand, twenty-one".