80731561689 has 27 divisors (see below), whose sum is σ = 118920548383. Its totient is φ = 52775999952.

The previous prime is 80731561649. The next prime is 80731561699. The reversal of 80731561689 is 98616513708.

The square root of 80731561689 is 284133.

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

80731561689 is a `hidden beast` number, since 8 + 0 + 7 + 3 + 15 + 616 + 8 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 58199150025 + 22532411664 = 241245^2 + 150108^2 .

It is a de Polignac number, because none of the positive numbers 2^k-80731561689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (80731561649) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 45176254 + ... + 45178040.

Almost surely, 2^80731561689 is an apocalyptic number.

80731561689 is the 284133-rd square number.

80731561689 is the 142067-th centered octagonal number.

It is an amenable number.

80731561689 is a deficient number, since it is larger than the sum of its proper divisors (38188986694).

80731561689 is an frugal number, since it uses more digits than its factorization.

80731561689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3686 (or 1843 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 80731561689 in words is "eighty billion, seven hundred thirty-one million, five hundred sixty-one thousand, six hundred eighty-nine".