66168816289 has 9 divisors (see below), whose sum is σ = 67132427089. Its totient is φ = 65218854820.

The previous prime is 66168816281. The next prime is 66168816313. The reversal of 66168816289 is 98261886166.

The square root of 66168816289 is 257233.

It is a perfect power (a square), and thus also a powerful number.

66168816289 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66168816289 - 2³ = 66168816281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66168816281) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 18261732 + ... + 18265354.

Almost surely, 2^66168816289 is an apocalyptic number.

66168816289 is the 257233-rd square number.

66168816289 is the 128617-th centered octagonal number.

It is an amenable number.

66168816289 is a deficient number, since it is larger than the sum of its proper divisors (963610800).

66168816289 is an frugal number, since it uses more digits than its factorization.

66168816289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7388 (or 3694 counting only the distinct ones).

The product of its digits is 11943936, while the sum is 61.

The spelling of 66168816289 in words is "sixty-six billion, one hundred sixty-eight million, eight hundred sixteen thousand, two hundred eighty-nine".