6661660517 has 2 divisors, whose sum is σ = 6661660518. Its totient is φ = 6661660516.

The previous prime is 6661660513. The next prime is 6661660541. The reversal of 6661660517 is 7150661666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6510714721 + 150945796 = 80689^2 + 12286^2 .

It is a cyclic number.

It is not a de Polignac number, because 6661660517 - 2² = 6661660513 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6661660513) 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, 3330830258 + 3330830259.

It is an arithmetic number, because the mean of its divisors is an integer number (3330830259).

Almost surely, 2^6661660517 is an apocalyptic number.

It is an amenable number.

6661660517 is a deficient number, since it is larger than the sum of its proper divisors (1).

6661660517 is an equidigital number, since it uses as much as digits as its factorization.

6661660517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 6661660517 is about 81618.9960548401. The cubic root of 6661660517 is about 1881.6008430736.

The spelling of 6661660517 in words is "six billion, six hundred sixty-one million, six hundred sixty thousand, five hundred seventeen".