1221221210111 has 12 divisors (see below), whose sum is σ = 1420811050392. Its totient is φ = 1046608669008.

The previous prime is 1221221210081. The next prime is 1221221210113. The reversal of 1221221210111 is 1110121221221.

It is not a de Polignac number, because 1221221210111 - 2¹⁴ = 1221221193727 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221221210111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221210113) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1473200 + ... + 2147733.

It is an arithmetic number, because the mean of its divisors is an integer number (118400920866).

Almost surely, 2^{1221221210111} is an apocalyptic number.

1221221210111 is a deficient number, since it is larger than the sum of its proper divisors (199589840281).

1221221210111 is an equidigital number, since it uses as much as digits as its factorization.

1221221210111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3627830 (or 3627823 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1221221210111 its reverse (1110121221221), we get a palindrome (2331342431332).

The spelling of 1221221210111 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred ten thousand, one hundred eleven".