1665664005917 has 2 divisors, whose sum is σ = 1665664005918. Its totient is φ = 1665664005916.

The previous prime is 1665664005869. The next prime is 1665664005923. The reversal of 1665664005917 is 7195004665661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1326760726201 + 338903279716 = 1151851^2 + 582154^2 .

It is an emirp because it is prime and its reverse (7195004665661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1665664005917 - 2²⁴ = 1665647228701 is a prime.

It is a super-2 number, since 2×1665664005917² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665664005997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832832002958 + 832832002959.

It is an arithmetic number, because the mean of its divisors is an integer number (832832002959).

Almost surely, 2^{1665664005917} is an apocalyptic number.

It is an amenable number.

1665664005917 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665664005917 is an equidigital number, since it uses as much as digits as its factorization.

1665664005917 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8164800, while the sum is 56.

The spelling of 1665664005917 in words is "one trillion, six hundred sixty-five billion, six hundred sixty-four million, five thousand, nine hundred seventeen".