1221201001021 has 8 divisors (see below), whose sum is σ = 1223326307000. Its totient is φ = 1219076006400.

The previous prime is 1221201000979. The next prime is 1221201001133. The reversal of 1221201001021 is 1201001021221.

It can be written as a sum of positive squares in 4 ways, for example, as 1134947184921 + 86253816100 = 1065339^2 + 293690^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221201001021 - 2¹⁷ = 1221200869949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221201000992 and 1221201001010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221201001621) 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 7 ways as a sum of consecutive naturals, for example, 8613535 + ... + 8754163.

It is an arithmetic number, because the mean of its divisors is an integer number (152915788375).

Almost surely, 2^{1221201001021} is an apocalyptic number.

It is an amenable number.

1221201001021 is a deficient number, since it is larger than the sum of its proper divisors (2125305979).

1221201001021 is a wasteful number, since it uses less digits than its factorization.

1221201001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155679.

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

Adding to 1221201001021 its reverse (1201001021221), we get a palindrome (2422202022242).

The spelling of 1221201001021 in words is "one trillion, two hundred twenty-one billion, two hundred one million, one thousand, twenty-one".