311203101221 has 2 divisors, whose sum is σ = 311203101222. Its totient is φ = 311203101220.

The previous prime is 311203101211. The next prime is 311203101257. The reversal of 311203101221 is 122101302113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 234024705121 + 77178396100 = 483761^2 + 277810^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-311203101221 is a prime.

It is a Sophie Germain 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 311203101221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311203101211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155601550610 + 155601550611.

It is an arithmetic number, because the mean of its divisors is an integer number (155601550611).

Almost surely, 2^311203101221 is an apocalyptic number.

It is an amenable number.

311203101221 is a deficient number, since it is larger than the sum of its proper divisors (1).

311203101221 is an equidigital number, since it uses as much as digits as its factorization.

311203101221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 311203101221 its reverse (122101302113), we get a palindrome (433304403334).

The spelling of 311203101221 in words is "three hundred eleven billion, two hundred three million, one hundred one thousand, two hundred twenty-one".