79840718721 has 27 divisors (see below), whose sum is σ = 116646792483. Its totient is φ = 52624160640.

The previous prime is 79840718693. The next prime is 79840718761. The reversal of 79840718721 is 12781704897.

The square root of 79840718721 is 282561.

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., 35851529025 + 43989189696 = 189345^2 + 209736^2 .

It is not a de Polignac number, because 79840718721 - 2²³ = 79832330113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (79840718761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 82224766 + ... + 82225736.

Almost surely, 2^79840718721 is an apocalyptic number.

79840718721 is the 282561-st square number.

79840718721 is the 141281-st centered octagonal number.

It is an amenable number.

79840718721 is a deficient number, since it is larger than the sum of its proper divisors (36806073762).

79840718721 is an frugal number, since it uses more digits than its factorization.

79840718721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142 (or 1071 counting only the distinct ones).

The product of its (nonzero) digits is 1580544, while the sum is 54.

The spelling of 79840718721 in words is "seventy-nine billion, eight hundred forty million, seven hundred eighteen thousand, seven hundred twenty-one".