1221200121111 has 8 divisors (see below), whose sum is σ = 1628369176320. Its totient is φ = 814082239992.

The previous prime is 1221200121109. The next prime is 1221200121161. The reversal of 1221200121111 is 1111210021221.

It is a happy number.

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

It is not a de Polignac number, because 1221200121111 - 2¹ = 1221200121109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221200121161) 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, 12737805 + ... + 12833318.

It is an arithmetic number, because the mean of its divisors is an integer number (203546147040).

Almost surely, 2^{1221200121111} is an apocalyptic number.

1221200121111 is a deficient number, since it is larger than the sum of its proper divisors (407169055209).

1221200121111 is a wasteful number, since it uses less digits than its factorization.

1221200121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25587045.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1221200121111 its reverse (1111210021221), we get a palindrome (2332410142332).

The spelling of 1221200121111 in words is "one trillion, two hundred twenty-one billion, two hundred million, one hundred twenty-one thousand, one hundred eleven".