617806136561 has 2 divisors, whose sum is σ = 617806136562. Its totient is φ = 617806136560.

The previous prime is 617806136543. The next prime is 617806136653. The reversal of 617806136561 is 165631608716.

617806136561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 418568886961 + 199237249600 = 646969^2 + 446360^2 .

It is a cyclic number.

It is not a de Polignac number, because 617806136561 - 2¹⁰ = 617806135537 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 (617806136461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 308903068280 + 308903068281.

It is an arithmetic number, because the mean of its divisors is an integer number (308903068281).

Almost surely, 2^617806136561 is an apocalyptic number.

It is an amenable number.

617806136561 is a deficient number, since it is larger than the sum of its proper divisors (1).

617806136561 is an equidigital number, since it uses as much as digits as its factorization.

617806136561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 617806136561 in words is "six hundred seventeen billion, eight hundred six million, one hundred thirty-six thousand, five hundred sixty-one".