66681183529 has 9 divisors (see below), whose sum is σ = 67652183991. Its totient is φ = 65723936040.

The previous prime is 66681183511. The next prime is 66681183533. The reversal of 66681183529 is 92538118666.

The square root of 66681183529 is 258227.

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., 1784640025 + 64896543504 = 42245^2 + 254748^2 .

It is not a de Polignac number, because 66681183529 - 2⁹ = 66681183017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66681183529.

It is not an unprimeable number, because it can be changed into a prime (66681180529) 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, 18332299 + ... + 18335935.

Almost surely, 2^66681183529 is an apocalyptic number.

66681183529 is the 258227-th square number.

66681183529 is the 129114-th centered octagonal number.

It is an amenable number.

66681183529 is a deficient number, since it is larger than the sum of its proper divisors (971000462).

66681183529 is an frugal number, since it uses more digits than its factorization.

66681183529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7416 (or 3708 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 55.

The spelling of 66681183529 in words is "sixty-six billion, six hundred eighty-one million, one hundred eighty-three thousand, five hundred twenty-nine".