312012111221 has 2 divisors, whose sum is σ = 312012111222. Its totient is φ = 312012111220.

The previous prime is 312012111211. The next prime is 312012111289. The reversal of 312012111221 is 122111210213.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 307759767121 + 4252344100 = 554761^2 + 65210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-312012111221 is a prime.

It is a super-2 number, since 2×312012111221² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 312012111221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312012111211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156006055610 + 156006055611.

It is an arithmetic number, because the mean of its divisors is an integer number (156006055611).

Almost surely, 2^312012111221 is an apocalyptic number.

It is an amenable number.

312012111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

312012111221 is an equidigital number, since it uses as much as digits as its factorization.

312012111221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 312012111221 its reverse (122111210213), we get a palindrome (434123321434).

The spelling of 312012111221 in words is "three hundred twelve billion, twelve million, one hundred eleven thousand, two hundred twenty-one".