1221020120121 has 16 divisors (see below), whose sum is σ = 1671244523520. Its totient is φ = 792526306320.

The previous prime is 1221020120071. The next prime is 1221020120123. The reversal of 1221020120121 is 1210210201221.

It is not a de Polignac number, because 1221020120121 - 2⁷ = 1221020119993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221020120121.

It is not an unprimeable number, because it can be changed into a prime (1221020120123) 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, 15177361 + ... + 15257598.

It is an arithmetic number, because the mean of its divisors is an integer number (104452782720).

Almost surely, 2^{1221020120121} is an apocalyptic number.

It is an amenable number.

1221020120121 is a deficient number, since it is larger than the sum of its proper divisors (450224403399).

1221020120121 is a wasteful number, since it uses less digits than its factorization.

1221020120121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30435316.

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

Adding to 1221020120121 its reverse (1210210201221), we get a palindrome (2431230321342).

The spelling of 1221020120121 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred twenty thousand, one hundred twenty-one".