31311220117 has 2 divisors, whose sum is σ = 31311220118. Its totient is φ = 31311220116.

The previous prime is 31311220099. The next prime is 31311220121. The reversal of 31311220117 is 71102211313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30086290116 + 1224930001 = 173454^2 + 34999^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31311220117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31311220217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15655610058 + 15655610059.

It is an arithmetic number, because the mean of its divisors is an integer number (15655610059).

Almost surely, 2^31311220117 is an apocalyptic number.

It is an amenable number.

31311220117 is a deficient number, since it is larger than the sum of its proper divisors (1).

31311220117 is an equidigital number, since it uses as much as digits as its factorization.

31311220117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 22.

The spelling of 31311220117 in words is "thirty-one billion, three hundred eleven million, two hundred twenty thousand, one hundred seventeen".