20431312117 has 2 divisors, whose sum is σ = 20431312118. Its totient is φ = 20431312116.

The previous prime is 20431312039. The next prime is 20431312141. The reversal of 20431312117 is 71121313402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20380703121 + 50608996 = 142761^2 + 7114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20431312117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20431312091 and 20431312100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20431312177) 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, 10215656058 + 10215656059.

It is an arithmetic number, because the mean of its divisors is an integer number (10215656059).

Almost surely, 2^20431312117 is an apocalyptic number.

It is an amenable number.

20431312117 is a deficient number, since it is larger than the sum of its proper divisors (1).

20431312117 is an equidigital number, since it uses as much as digits as its factorization.

20431312117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

Adding to 20431312117 its reverse (71121313402), we get a palindrome (91552625519).

The spelling of 20431312117 in words is "twenty billion, four hundred thirty-one million, three hundred twelve thousand, one hundred seventeen".