20995807717 has 2 divisors, whose sum is σ = 20995807718. Its totient is φ = 20995807716.

The previous prime is 20995807667. The next prime is 20995807739. The reversal of 20995807717 is 71770859902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20163716001 + 832091716 = 141999^2 + 28846^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20995807717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20095807717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10497903858 + 10497903859.

It is an arithmetic number, because the mean of its divisors is an integer number (10497903859).

Almost surely, 2^20995807717 is an apocalyptic number.

It is an amenable number.

20995807717 is a deficient number, since it is larger than the sum of its proper divisors (1).

20995807717 is an equidigital number, since it uses as much as digits as its factorization.

20995807717 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2222640, while the sum is 55.

The spelling of 20995807717 in words is "twenty billion, nine hundred ninety-five million, eight hundred seven thousand, seven hundred seventeen".