12011212221 has 4 divisors (see below), whose sum is σ = 16014949632. Its totient is φ = 8007474812.

The previous prime is 12011212217. The next prime is 12011212223. The reversal of 12011212221 is 12221211021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12011212221 - 2² = 12011212217 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 12011212221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12011212223) 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, 2001868701 + ... + 2001868706.

It is an arithmetic number, because the mean of its divisors is an integer number (4003737408).

Almost surely, 2^12011212221 is an apocalyptic number.

It is an amenable number.

12011212221 is a deficient number, since it is larger than the sum of its proper divisors (4003737411).

12011212221 is an equidigital number, since it uses as much as digits as its factorization.

12011212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4003737410.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 12011212221 its reverse (12221211021), we get a palindrome (24232423242).

The spelling of 12011212221 in words is "twelve billion, eleven million, two hundred twelve thousand, two hundred twenty-one".