665581185566 has 32 divisors (see below), whose sum is σ = 1146667777920. Its totient is φ = 286560871200.

The previous prime is 665581185553. The next prime is 665581185569.

665581185566 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 665581185499 and 665581185508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665581185569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2157356 + ... + 2446496.

It is an arithmetic number, because the mean of its divisors is an integer number (35833368060).

Almost surely, 2^665581185566 is an apocalyptic number.

665581185566 is a deficient number, since it is larger than the sum of its proper divisors (481086592354).

665581185566 is a wasteful number, since it uses less digits than its factorization.

665581185566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294680.

The product of its digits is 51840000, while the sum is 62.

The spelling of 665581185566 in words is "six hundred sixty-five billion, five hundred eighty-one million, one hundred eighty-five thousand, five hundred sixty-six".