80491931521 has 9 divisors (see below), whose sum is σ = 81850701699. Its totient is φ = 79155369000.

The previous prime is 80491931503. The next prime is 80491931537. The reversal of 80491931521 is 12513919408.

The square root of 80491931521 is 283711.

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., 2617447921 + 77874483600 = 51161^2 + 279060^2 .

It is not a de Polignac number, because 80491931521 - 2¹³ = 80491923329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (80491931591) 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 8 ways as a sum of consecutive naturals, for example, 17304046 + ... + 17308696.

It is an arithmetic number, because the mean of its divisors is an integer number (9094522411).

Almost surely, 2^80491931521 is an apocalyptic number.

80491931521 is the 283711-st square number.

80491931521 is the 141856-th centered octagonal number.

It is an amenable number.

80491931521 is a deficient number, since it is larger than the sum of its proper divisors (1358770178).

80491931521 is an frugal number, since it uses more digits than its factorization.

80491931521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9424 (or 4712 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 43.

The spelling of 80491931521 in words is "eighty billion, four hundred ninety-one million, nine hundred thirty-one thousand, five hundred twenty-one".