1166165065561 has 8 divisors (see below), whose sum is σ = 1237781998440. Its totient is φ = 1094883575808.

The previous prime is 1166165065487. The next prime is 1166165065573. The reversal of 1166165065561 is 1655605616611.

It can be written as a sum of positive squares in 4 ways, for example, as 522208569600 + 643956495961 = 722640^2 + 802469^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1166165065561 - 2¹⁷ = 1166164934489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1166165965561) 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 in 7 ways as a sum of consecutive naturals, for example, 83853616 + ... + 83867521.

It is an arithmetic number, because the mean of its divisors is an integer number (154722749805).

Almost surely, 2^{1166165065561} is an apocalyptic number.

It is an amenable number.

1166165065561 is a deficient number, since it is larger than the sum of its proper divisors (71616932879).

1166165065561 is a wasteful number, since it uses less digits than its factorization.

1166165065561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167721563.

The product of its (nonzero) digits is 972000, while the sum is 49.

The spelling of 1166165065561 in words is "one trillion, one hundred sixty-six billion, one hundred sixty-five million, sixty-five thousand, five hundred sixty-one".