66066155915881 has 9 divisors (see below), whose sum is σ = 72618269654973. Its totient is φ = 60060060460620.

The previous prime is 66066155915777. The next prime is 66066155915899. The reversal of 66066155915881 is 18851955166066.

The square root of 66066155915881 is 8128109.

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

It is not a de Polignac number, because 66066155915881 - 2³⁵ = 66031796177513 is a prime.

It is a super-2 number, since 2×66066155915881² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66066155975881) 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, 89039740 + ... + 89778658.

Almost surely, 2^{66066155915881} is an apocalyptic number.

66066155915881 is the 8128109-th square number.

66066155915881 is the 4064055-th centered octagonal number.

It is an amenable number.

66066155915881 is a deficient number, since it is larger than the sum of its proper divisors (6552113739092).

66066155915881 is an frugal number, since it uses more digits than its factorization.

66066155915881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1477860 (or 738930 counting only the distinct ones).

The product of its (nonzero) digits is 93312000, while the sum is 67.

The spelling of 66066155915881 in words is "sixty-six trillion, sixty-six billion, one hundred fifty-five million, nine hundred fifteen thousand, eight hundred eighty-one".