11665566531661 has 16 divisors (see below), whose sum is σ = 13551129779328. Its totient is φ = 9834778699200.

The previous prime is 11665566531637. The next prime is 11665566531679. The reversal of 11665566531661 is 16613566556611.

It is not a de Polignac number, because 11665566531661 - 2¹¹ = 11665566529613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11665566531596 and 11665566531605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11665566531691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11540571 + ... + 12510631.

It is an arithmetic number, because the mean of its divisors is an integer number (846945611208).

Almost surely, 2^{11665566531661} is an apocalyptic number.

It is an amenable number.

11665566531661 is a deficient number, since it is larger than the sum of its proper divisors (1885563247667).

11665566531661 is an equidigital number, since it uses as much as digits as its factorization.

11665566531661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998292.

The product of its digits is 17496000, while the sum is 58.

The spelling of 11665566531661 in words is "eleven trillion, six hundred sixty-five billion, five hundred sixty-six million, five hundred thirty-one thousand, six hundred sixty-one".