1221021021021 has 16 divisors (see below), whose sum is σ = 1638338075136. Its totient is φ = 808864160576.

The previous prime is 1221021020987. The next prime is 1221021021023. The reversal of 1221021021021 is 1201201201221.

It is a cyclic number.

It is not a de Polignac number, because 1221021021021 - 2⁷ = 1221021020893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221021021023) 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 15 ways as a sum of consecutive naturals, for example, 300871 + ... + 1591403.

It is an arithmetic number, because the mean of its divisors is an integer number (102396129696).

Almost surely, 2^{1221021021021} is an apocalyptic number.

It is an amenable number.

1221021021021 is a deficient number, since it is larger than the sum of its proper divisors (417317054115).

1221021021021 is a wasteful number, since it uses less digits than its factorization.

1221021021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1292532.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1221021021021 its reverse (1201201201221), we get a palindrome (2422222222242).

It can be divided in two parts, 12 and 21021021021, that multiplied together give a palindrome (252252252252).

The spelling of 1221021021021 in words is "one trillion, two hundred twenty-one billion, twenty-one million, twenty-one thousand, twenty-one".