6665166817 has 2 divisors, whose sum is σ = 6665166818. Its totient is φ = 6665166816.

The previous prime is 6665166793. The next prime is 6665166847. The reversal of 6665166817 is 7186615666.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4009928976 + 2655237841 = 63324^2 + 51529^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6665166817 is a prime.

It is a super-2 number, since 2×6665166817² = 88848897396875822978, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6665166847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332583408 + 3332583409.

It is an arithmetic number, because the mean of its divisors is an integer number (3332583409).

Almost surely, 2^6665166817 is an apocalyptic number.

It is an amenable number.

6665166817 is a deficient number, since it is larger than the sum of its proper divisors (1).

6665166817 is an equidigital number, since it uses as much as digits as its factorization.

6665166817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 52.

The square root of 6665166817 is about 81640.4729101933. The cubic root of 6665166817 is about 1881.9309059188.

The spelling of 6665166817 in words is "six billion, six hundred sixty-five million, one hundred sixty-six thousand, eight hundred seventeen".