64765409561 has 2 divisors, whose sum is σ = 64765409562. Its totient is φ = 64765409560.

The previous prime is 64765409551. The next prime is 64765409567. The reversal of 64765409561 is 16590456746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33945851536 + 30819558025 = 184244^2 + 175555^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64765409561 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 (64765409567) 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, 32382704780 + 32382704781.

It is an arithmetic number, because the mean of its divisors is an integer number (32382704781).

Almost surely, 2^64765409561 is an apocalyptic number.

It is an amenable number.

64765409561 is a deficient number, since it is larger than the sum of its proper divisors (1).

64765409561 is an equidigital number, since it uses as much as digits as its factorization.

64765409561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5443200, while the sum is 53.

The spelling of 64765409561 in words is "sixty-four billion, seven hundred sixty-five million, four hundred nine thousand, five hundred sixty-one".