6561161616517 has 2 divisors, whose sum is σ = 6561161616518. Its totient is φ = 6561161616516.

The previous prime is 6561161616511. The next prime is 6561161616643. The reversal of 6561161616517 is 7156161611656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5314989041476 + 1246172575041 = 2305426^2 + 1116321^2 .

It is a cyclic number.

It is not a de Polignac number, because 6561161616517 - 2¹⁹ = 6561161092229 is a prime.

It is a super-2 number, since 2×6561161616517² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6561161616511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280580808258 + 3280580808259.

It is an arithmetic number, because the mean of its divisors is an integer number (3280580808259).

Almost surely, 2^{6561161616517} is an apocalyptic number.

It is an amenable number.

6561161616517 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561161616517 is an equidigital number, since it uses as much as digits as its factorization.

6561161616517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1360800, while the sum is 52.

The spelling of 6561161616517 in words is "six trillion, five hundred sixty-one billion, one hundred sixty-one million, six hundred sixteen thousand, five hundred seventeen".