31217910121 has 2 divisors, whose sum is σ = 31217910122. Its totient is φ = 31217910120.

The previous prime is 31217910079. The next prime is 31217910149. The reversal of 31217910121 is 12101971213.

It is an a-pointer prime, because the next prime (31217910149) can be obtained adding 31217910121 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15677794521 + 15540115600 = 125211^2 + 124660^2 .

It is a cyclic number.

It is not a de Polignac number, because 31217910121 - 2⁷ = 31217909993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31217910121.

It is not a weakly prime, because it can be changed into another prime (31217914121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15608955060 + 15608955061.

It is an arithmetic number, because the mean of its divisors is an integer number (15608955061).

Almost surely, 2^31217910121 is an apocalyptic number.

It is an amenable number.

31217910121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31217910121 is an equidigital number, since it uses as much as digits as its factorization.

31217910121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 756, while the sum is 28.

The spelling of 31217910121 in words is "thirty-one billion, two hundred seventeen million, nine hundred ten thousand, one hundred twenty-one".