1001221021021 has 16 divisors (see below), whose sum is σ = 1131266149888. Its totient is φ = 879728817600.

The previous prime is 1001221021019. The next prime is 1001221021063. The reversal of 1001221021021 is 1201201221001.

It is a cyclic number.

It is not a de Polignac number, because 1001221021021 - 2¹ = 1001221021019 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a junction number, because it is equal to n+sod(n) for n = 1001221020992 and 1001221021010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001221021081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20339511 + ... + 20388676.

It is an arithmetic number, because the mean of its divisors is an integer number (70704134368).

Almost surely, 2^{1001221021021} is an apocalyptic number.

It is an amenable number.

1001221021021 is a deficient number, since it is larger than the sum of its proper divisors (130045128867).

1001221021021 is a wasteful number, since it uses less digits than its factorization.

1001221021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40728292.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1001221021021 its reverse (1201201221001), we get a palindrome (2202422242022).

The spelling of 1001221021021 in words is "one trillion, one billion, two hundred twenty-one million, twenty-one thousand, twenty-one".