31343312211221 has 2 divisors, whose sum is σ = 31343312211222. Its totient is φ = 31343312211220.

The previous prime is 31343312211103. The next prime is 31343312211241. The reversal of 31343312211221 is 12211221334313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29952481168996 + 1390831042225 = 5472886^2 + 1179335^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31343312211221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31343312211241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15671656105610 + 15671656105611.

It is an arithmetic number, because the mean of its divisors is an integer number (15671656105611).

Almost surely, 2^{31343312211221} is an apocalyptic number.

It is an amenable number.

31343312211221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31343312211221 is an equidigital number, since it uses as much as digits as its factorization.

31343312211221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 29.

Adding to 31343312211221 its reverse (12211221334313), we get a palindrome (43554533545534).

The spelling of 31343312211221 in words is "thirty-one trillion, three hundred forty-three billion, three hundred twelve million, two hundred eleven thousand, two hundred twenty-one".