1221200120101 has 8 divisors (see below), whose sum is σ = 1360488197880. Its totient is φ = 1088390557632.

The previous prime is 1221200120081. The next prime is 1221200120123. The reversal of 1221200120101 is 1010210021221.

It can be written as a sum of positive squares in 4 ways, for example, as 50636250625 + 1170563869476 = 225025^2 + 1081926^2 .

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 1221200120101 - 2⁹ = 1221200119589 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221200120171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1619628430 + ... + 1619629183.

It is an arithmetic number, because the mean of its divisors is an integer number (170061024735).

Almost surely, 2^{1221200120101} is an apocalyptic number.

It is an amenable number.

1221200120101 is a deficient number, since it is larger than the sum of its proper divisors (139288077779).

1221200120101 is a wasteful number, since it uses less digits than its factorization.

1221200120101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3239257655.

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

Adding to 1221200120101 its reverse (1010210021221), we get a palindrome (2231410141322).

The spelling of 1221200120101 in words is "one trillion, two hundred twenty-one billion, two hundred million, one hundred twenty thousand, one hundred one".