11665664531 has 4 divisors (see below), whose sum is σ = 11717977152. Its totient is φ = 11613351912.

The previous prime is 11665664509. The next prime is 11665664539. The reversal of 11665664531 is 13546656611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13546656611 = 17299 ⋅783089.

It is a cyclic number.

It is not a de Polignac number, because 11665664531 - 2¹⁴ = 11665648147 is a prime.

It is a super-2 number, since 2×11665664531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11665664539) 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 3 ways as a sum of consecutive naturals, for example, 26155976 + ... + 26156421.

It is an arithmetic number, because the mean of its divisors is an integer number (2929494288).

Almost surely, 2^11665664531 is an apocalyptic number.

11665664531 is a deficient number, since it is larger than the sum of its proper divisors (52312621).

11665664531 is an equidigital number, since it uses as much as digits as its factorization.

11665664531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52312620.

The product of its digits is 388800, while the sum is 44.

The spelling of 11665664531 in words is "eleven billion, six hundred sixty-five million, six hundred sixty-four thousand, five hundred thirty-one".