1221201121111 has 4 divisors (see below), whose sum is σ = 1244242651752. Its totient is φ = 1198159590472.

The previous prime is 1221201121099. The next prime is 1221201121187. The reversal of 1221201121111 is 1111211021221.

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 1221201121111 - 2⁷ = 1221201120983 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 (1221201121711) 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, 11520765241 + ... + 11520765346.

It is an arithmetic number, because the mean of its divisors is an integer number (311060662938).

Almost surely, 2^{1221201121111} is an apocalyptic number.

1221201121111 is a deficient number, since it is larger than the sum of its proper divisors (23041530641).

1221201121111 is an equidigital number, since it uses as much as digits as its factorization.

1221201121111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23041530640.

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

Adding to 1221201121111 its reverse (1111211021221), we get a palindrome (2332412142332).

The spelling of 1221201121111 in words is "one trillion, two hundred twenty-one billion, two hundred one million, one hundred twenty-one thousand, one hundred eleven".