31212101123221 has 2 divisors, whose sum is σ = 31212101123222. Its totient is φ = 31212101123220.

The previous prime is 31212101123219. The next prime is 31212101123243. The reversal of 31212101123221 is 12232110121213.

It is a happy number.

It is an a-pointer prime, because the next prime (31212101123243) can be obtained adding 31212101123221 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31176309780625 + 35791342596 = 5583575^2 + 189186^2 .

It is a cyclic number.

It is not a de Polignac number, because 31212101123221 - 2¹ = 31212101123219 is a prime.

Together with 31212101123219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 31212101123192 and 31212101123201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31212101123251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15606050561610 + 15606050561611.

It is an arithmetic number, because the mean of its divisors is an integer number (15606050561611).

Almost surely, 2^{31212101123221} is an apocalyptic number.

It is an amenable number.

31212101123221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31212101123221 is an equidigital number, since it uses as much as digits as its factorization.

31212101123221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 22.

Adding to 31212101123221 its reverse (12232110121213), we get a palindrome (43444211244434).

The spelling of 31212101123221 in words is "thirty-one trillion, two hundred twelve billion, one hundred one million, one hundred twenty-three thousand, two hundred twenty-one".