20716217513 has 2 divisors, whose sum is σ = 20716217514. Its totient is φ = 20716217512.

The previous prime is 20716217491. The next prime is 20716217551. The reversal of 20716217513 is 31571261702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19164802969 + 1551414544 = 138437^2 + 39388^2 .

It is a cyclic number.

It is not a de Polignac number, because 20716217513 - 2²² = 20712023209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20716217563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10358108756 + 10358108757.

It is an arithmetic number, because the mean of its divisors is an integer number (10358108757).

Almost surely, 2^20716217513 is an apocalyptic number.

It is an amenable number.

20716217513 is a deficient number, since it is larger than the sum of its proper divisors (1).

20716217513 is an equidigital number, since it uses as much as digits as its factorization.

20716217513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17640, while the sum is 35.

The spelling of 20716217513 in words is "twenty billion, seven hundred sixteen million, two hundred seventeen thousand, five hundred thirteen".