13665564866 has 4 divisors (see below), whose sum is σ = 20498347302. Its totient is φ = 6832782432.

The previous prime is 13665564827. The next prime is 13665564911. The reversal of 13665564866 is 66846556631.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66846556631 = 2053 ⋅32560427.

It can be written as a sum of positive squares in only one way, i.e., 13427942641 + 237622225 = 115879^2 + 15415^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3416391215 + ... + 3416391218.

Almost surely, 2^13665564866 is an apocalyptic number.

13665564866 is a deficient number, since it is larger than the sum of its proper divisors (6832782436).

13665564866 is an equidigital number, since it uses as much as digits as its factorization.

13665564866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6832782435.

The product of its digits is 18662400, while the sum is 56.

The spelling of 13665564866 in words is "thirteen billion, six hundred sixty-five million, five hundred sixty-four thousand, eight hundred sixty-six".