31123312117 has 2 divisors, whose sum is σ = 31123312118. Its totient is φ = 31123312116.

The previous prime is 31123312081. The next prime is 31123312261. The reversal of 31123312117 is 71121332113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30979168081 + 144144036 = 176009^2 + 12006^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31123312117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31123312091 and 31123312100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31123318117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15561656058 + 15561656059.

It is an arithmetic number, because the mean of its divisors is an integer number (15561656059).

Almost surely, 2^31123312117 is an apocalyptic number.

It is an amenable number.

31123312117 is a deficient number, since it is larger than the sum of its proper divisors (1).

31123312117 is an equidigital number, since it uses as much as digits as its factorization.

31123312117 is an evil number, because the sum of its binary digits is even.

The product of its digits is 756, while the sum is 25.

The spelling of 31123312117 in words is "thirty-one billion, one hundred twenty-three million, three hundred twelve thousand, one hundred seventeen".