31221220241 has 2 divisors, whose sum is σ = 31221220242. Its totient is φ = 31221220240.

The previous prime is 31221220237. The next prime is 31221220291. The reversal of 31221220241 is 14202212213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30173079616 + 1048140625 = 173704^2 + 32375^2 .

It is a cyclic number.

It is not a de Polignac number, because 31221220241 - 2² = 31221220237 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31221220291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610610120 + 15610610121.

It is an arithmetic number, because the mean of its divisors is an integer number (15610610121).

Almost surely, 2^31221220241 is an apocalyptic number.

It is an amenable number.

31221220241 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221220241 is an equidigital number, since it uses as much as digits as its factorization.

31221220241 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 31221220241 its reverse (14202212213), we get a palindrome (45423432454).

The spelling of 31221220241 in words is "thirty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred forty-one".