1166515605665 has 4 divisors (see below), whose sum is σ = 1399818726804. Its totient is φ = 933212484528.

The previous prime is 1166515605659. The next prime is 1166515605679. The reversal of 1166515605665 is 5665065156611.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 132472705024 + 1034042900641 = 363968^2 + 1016879^2 .

It is a cyclic number.

It is not a de Polignac number, because 1166515605665 - 2¹² = 1166515601569 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116651560562 + ... + 116651560571.

It is an arithmetic number, because the mean of its divisors is an integer number (349954681701).

Almost surely, 2^{1166515605665} is an apocalyptic number.

It is an amenable number.

1166515605665 is a deficient number, since it is larger than the sum of its proper divisors (233303121139).

1166515605665 is an equidigital number, since it uses as much as digits as its factorization.

1166515605665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233303121138.

The product of its (nonzero) digits is 4860000, while the sum is 53.

The spelling of 1166515605665 in words is "one trillion, one hundred sixty-six billion, five hundred fifteen million, six hundred five thousand, six hundred sixty-five".