1001011219921 has 2 divisors, whose sum is σ = 1001011219922. Its totient is φ = 1001011219920.

The previous prime is 1001011219891. The next prime is 1001011220039. The reversal of 1001011219921 is 1299121101001.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 995532999696 + 5478220225 = 997764^2 + 74015^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001011219921 - 2⁹ = 1001011219409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1001011219921.

It is not a weakly prime, because it can be changed into another prime (1001011219721) 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 as a sum of consecutive naturals, namely, 500505609960 + 500505609961.

It is an arithmetic number, because the mean of its divisors is an integer number (500505609961).

Almost surely, 2^{1001011219921} is an apocalyptic number.

It is an amenable number.

1001011219921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001011219921 is an equidigital number, since it uses as much as digits as its factorization.

1001011219921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 28.

The spelling of 1001011219921 in words is "one trillion, one billion, eleven million, two hundred nineteen thousand, nine hundred twenty-one".