64785766517 has 2 divisors, whose sum is σ = 64785766518. Its totient is φ = 64785766516.

The previous prime is 64785766481. The next prime is 64785766537. The reversal of 64785766517 is 71566758746.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60228031396 + 4557735121 = 245414^2 + 67511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64785766517 is a prime.

It is a super-2 number, since 2×64785766517² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 64785766517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64785766537) 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, 32392883258 + 32392883259.

It is an arithmetic number, because the mean of its divisors is an integer number (32392883259).

Almost surely, 2^64785766517 is an apocalyptic number.

It is an amenable number.

64785766517 is a deficient number, since it is larger than the sum of its proper divisors (1).

64785766517 is an equidigital number, since it uses as much as digits as its factorization.

64785766517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 59270400, while the sum is 62.

The spelling of 64785766517 in words is "sixty-four billion, seven hundred eighty-five million, seven hundred sixty-six thousand, five hundred seventeen".