66166116865 has 8 divisors (see below), whose sum is σ = 79409903400. Its totient is φ = 52925851392.

The previous prime is 66166116859. The next prime is 66166116911. The reversal of 66166116865 is 56861166166.

It can be written as a sum of positive squares in 4 ways, for example, as 40452070129 + 25714046736 = 201127^2 + 160356^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 66166116865 - 2²⁹ = 65629245953 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 838744 + ... + 914233.

It is an arithmetic number, because the mean of its divisors is an integer number (9926237925).

Almost surely, 2^66166116865 is an apocalyptic number.

It is an amenable number.

66166116865 is a deficient number, since it is larger than the sum of its proper divisors (13243786535).

66166116865 is a wasteful number, since it uses less digits than its factorization.

66166116865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760531.

The product of its digits is 1866240, while the sum is 52.

The spelling of 66166116865 in words is "sixty-six billion, one hundred sixty-six million, one hundred sixteen thousand, eight hundred sixty-five".