1221011101111 has 4 divisors (see below), whose sum is σ = 1221023423224. Its totient is φ = 1220998779000.

The previous prime is 1221011101003. The next prime is 1221011101171. The reversal of 1221011101111 is 1111011101221.

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 1221011101111 - 2¹³ = 1221011092919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221011101091 and 1221011101100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221011101171) 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, 6011205 + ... + 6211006.

It is an arithmetic number, because the mean of its divisors is an integer number (305255855806).

Almost surely, 2^{1221011101111} is an apocalyptic number.

1221011101111 is a deficient number, since it is larger than the sum of its proper divisors (12322113).

1221011101111 is an equidigital number, since it uses as much as digits as its factorization.

1221011101111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12322112.

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 1221011101111 its reverse (1111011101221), we get a palindrome (2332022202332).

The spelling of 1221011101111 in words is "one trillion, two hundred twenty-one billion, eleven million, one hundred one thousand, one hundred eleven".