1665564613613 has 2 divisors, whose sum is σ = 1665564613614. Its totient is φ = 1665564613612.

The previous prime is 1665564613523. The next prime is 1665564613621. The reversal of 1665564613613 is 3163164655661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1290037096804 + 375527516809 = 1135798^2 + 612803^2 .

It is an emirp because it is prime and its reverse (3163164655661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1665564613613 - 2³⁰ = 1664490871789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665564613633) 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, 832782306806 + 832782306807.

It is an arithmetic number, because the mean of its divisors is an integer number (832782306807).

Almost surely, 2^{1665564613613} is an apocalyptic number.

It is an amenable number.

1665564613613 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665564613613 is an equidigital number, since it uses as much as digits as its factorization.

1665564613613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6998400, while the sum is 53.

The spelling of 1665564613613 in words is "one trillion, six hundred sixty-five billion, five hundred sixty-four million, six hundred thirteen thousand, six hundred thirteen".