1221200021111 has 4 divisors (see below), whose sum is σ = 1395657166992. Its totient is φ = 1046742875232.

The previous prime is 1221200021101. The next prime is 1221200021203. The reversal of 1221200021111 is 1111200021221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221200021111 - 2³⁰ = 1220126279287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221200021101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87228572930 + ... + 87228572943.

It is an arithmetic number, because the mean of its divisors is an integer number (348914291748).

Almost surely, 2^{1221200021111} is an apocalyptic number.

1221200021111 is a deficient number, since it is larger than the sum of its proper divisors (174457145881).

1221200021111 is an equidigital number, since it uses as much as digits as its factorization.

1221200021111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174457145880.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221200021111 its reverse (1111200021221), we get a palindrome (2332400042332).

The spelling of 1221200021111 in words is "one trillion, two hundred twenty-one billion, two hundred million, twenty-one thousand, one hundred eleven".