66163671729 has 27 divisors (see below), whose sum is σ = 96307699033. Its totient is φ = 43771123464.

The previous prime is 66163671689. The next prime is 66163671751. The reversal of 66163671729 is 92717636166.

It is a happy number.

The square root of 66163671729 is 257223.

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

66163671729 is a `hidden beast` number, since 6 + 616 + 3 + 6 + 7 + 17 + 2 + 9 = 666.

It is not a de Polignac number, because 66163671729 - 2¹⁷ = 66163540657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66163671229) by changing a digit.

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 26 ways as a sum of consecutive naturals, for example, 138128512 + ... + 138128990.

Almost surely, 2^66163671729 is an apocalyptic number.

66163671729 is the 257223-rd square number.

66163671729 is the 128612-nd centered octagonal number.

It is an amenable number.

66163671729 is a deficient number, since it is larger than the sum of its proper divisors (30144027304).

66163671729 is an frugal number, since it uses more digits than its factorization.

66163671729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1322 (or 661 counting only the distinct ones).

The product of its digits is 3429216, while the sum is 54.

The spelling of 66163671729 in words is "sixty-six billion, one hundred sixty-three million, six hundred seventy-one thousand, seven hundred twenty-nine".