31012220221 has 2 divisors, whose sum is σ = 31012220222. Its totient is φ = 31012220220.

The previous prime is 31012220219. The next prime is 31012220237. The reversal of 31012220221 is 12202221013.

It is a happy number.

It is an a-pointer prime, because the next prime (31012220237) can be obtained adding 31012220221 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28852759321 + 2159460900 = 169861^2 + 46470^2 .

It is a cyclic number.

It is not a de Polignac number, because 31012220221 - 2¹ = 31012220219 is a prime.

Together with 31012220219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 31012220195 and 31012220204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31012220201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15506110110 + 15506110111.

It is an arithmetic number, because the mean of its divisors is an integer number (15506110111).

Almost surely, 2^31012220221 is an apocalyptic number.

It is an amenable number.

31012220221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31012220221 is an equidigital number, since it uses as much as digits as its factorization.

31012220221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 31012220221 its reverse (12202221013), we get a palindrome (43214441234).

The spelling of 31012220221 in words is "thirty-one billion, twelve million, two hundred twenty thousand, two hundred twenty-one".