66081385969 has 9 divisors (see below), whose sum is σ = 67235824587. Its totient is φ = 64946452824.

The previous prime is 66081385963. The next prime is 66081385999. The reversal of 66081385969 is 96958318066.

The square root of 66081385969 is 257063.

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

It can be written as a sum of positive squares in only one way, i.e., 66020733025 + 60652944 = 256945^2 + 7788^2 .

It is not a de Polignac number, because 66081385969 - 2¹³ = 66081377777 is a prime.

It is a super-2 number, since 2×66081385969² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66081385963) 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, 15164539 + ... + 15168895.

Almost surely, 2^66081385969 is an apocalyptic number.

66081385969 is the 257063-rd square number.

66081385969 is the 128532-nd centered octagonal number.

It is an amenable number.

66081385969 is a deficient number, since it is larger than the sum of its proper divisors (1154438618).

66081385969 is an frugal number, since it uses more digits than its factorization.

66081385969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8832 (or 4416 counting only the distinct ones).

The product of its (nonzero) digits is 16796160, while the sum is 61.

The spelling of 66081385969 in words is "sixty-six billion, eighty-one million, three hundred eighty-five thousand, nine hundred sixty-nine".