312121011221 has 2 divisors, whose sum is σ = 312121011222. Its totient is φ = 312121011220.

The previous prime is 312121011203. The next prime is 312121011271. The reversal of 312121011221 is 122110121213.

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., 311911080100 + 209931121 = 558490^2 + 14489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-312121011221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 312121011221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312121011271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156060505610 + 156060505611.

It is an arithmetic number, because the mean of its divisors is an integer number (156060505611).

Almost surely, 2^312121011221 is an apocalyptic number.

It is an amenable number.

312121011221 is a deficient number, since it is larger than the sum of its proper divisors (1).

312121011221 is an equidigital number, since it uses as much as digits as its factorization.

312121011221 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 312121011221 its reverse (122110121213), we get a palindrome (434231132434).

The spelling of 312121011221 in words is "three hundred twelve billion, one hundred twenty-one million, eleven thousand, two hundred twenty-one".