12111211220221 has 4 divisors (see below), whose sum is σ = 12111551716572. Its totient is φ = 12110870723872.

The previous prime is 12111211220203. The next prime is 12111211220231. The reversal of 12111211220221 is 12202211211121.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7824965614596 + 4286245605625 = 2797314^2 + 2070325^2 .

It is a cyclic number.

It is not a de Polignac number, because 12111211220221 - 2³¹ = 12109063736573 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 (12111211220231) 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, 170194816 + ... + 170265961.

It is an arithmetic number, because the mean of its divisors is an integer number (3027887929143).

Almost surely, 2^{12111211220221} is an apocalyptic number.

It is an amenable number.

12111211220221 is a deficient number, since it is larger than the sum of its proper divisors (340496351).

12111211220221 is an equidigital number, since it uses as much as digits as its factorization.

12111211220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340496350.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 12111211220221 its reverse (12202211211121), we get a palindrome (24313422431342).

It can be divided in two parts, 1211121 and 1220221, that added together give a palindrome (2431342).

The spelling of 12111211220221 in words is "twelve trillion, one hundred eleven billion, two hundred eleven million, two hundred twenty thousand, two hundred twenty-one".