311202111221 has 2 divisors, whose sum is σ = 311202111222. Its totient is φ = 311202111220.

The previous prime is 311202111193. The next prime is 311202111239. The reversal of 311202111221 is 122111202113.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 269428474225 + 41773636996 = 519065^2 + 204386^2 .

It is a cyclic number.

It is not a de Polignac number, because 311202111221 - 2²⁶ = 311135002357 is a prime.

It is a super-2 number, since 2×311202111221² (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 311202111221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311202111281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155601055610 + 155601055611.

It is an arithmetic number, because the mean of its divisors is an integer number (155601055611).

Almost surely, 2^311202111221 is an apocalyptic number.

It is an amenable number.

311202111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

311202111221 is an equidigital number, since it uses as much as digits as its factorization.

311202111221 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 17.

Adding to 311202111221 its reverse (122111202113), we get a palindrome (433313313334).

The spelling of 311202111221 in words is "three hundred eleven billion, two hundred two million, one hundred eleven thousand, two hundred twenty-one".