12312011221 has 2 divisors, whose sum is σ = 12312011222. Its totient is φ = 12312011220.

The previous prime is 12312011209. The next prime is 12312011227. The reversal of 12312011221 is 12211021321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10993522500 + 1318488721 = 104850^2 + 36311^2 .

It is an emirp because it is prime and its reverse (12211021321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12312011221 - 2⁷ = 12312011093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12312011195 and 12312011204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12312011227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6156005610 + 6156005611.

It is an arithmetic number, because the mean of its divisors is an integer number (6156005611).

Almost surely, 2^12312011221 is an apocalyptic number.

It is an amenable number.

12312011221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12312011221 is an equidigital number, since it uses as much as digits as its factorization.

12312011221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 12312011221 its reverse (12211021321), we get a palindrome (24523032542).

The spelling of 12312011221 in words is "twelve billion, three hundred twelve million, eleven thousand, two hundred twenty-one".