12000001221 has 24 divisors (see below), whose sum is σ = 18674455800.
Its totient is φ = 7381535616.
The previous prime is 12000001159. The next prime is 12000001231. The reversal of 12000001221 is 12210000021.
Adding to 12000001221 its reverse (12210000021), we get a palindrome (24210001242).
It can be divided in two parts, 120000012 and 21, that multiplied together give a palindrome (2520000252).
12000001221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It can be written as a sum of positive squares in 4 ways, for example, as 3677088321 + 8322912900 = 60639^2 + 91230^2
It is not a de Polignac number, because 12000001221 - 213 = 11999993029 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (12000001231) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 278115 + ... + 318351.
It is an arithmetic number, because the mean of its divisors is an integer number (778102325).
Almost surely, 212000001221 is an apocalyptic number.
It is an amenable number.
12000001221 is a deficient number, since it is larger than the sum of its proper divisors (6674454579).
12000001221 is a wasteful number, since it uses less digits than its factorization.
12000001221 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 42805 (or 42802 counting only the distinct ones).
The product of its (nonzero) digits is 8, while the sum is 9.
The spelling of 12000001221 in words is "twelve billion, one thousand, two hundred twenty-one".