79779697209 has 9 divisors (see below), whose sum is σ = 115238564389. Its totient is φ = 53185899900.

The previous prime is 79779697181. The next prime is 79779697219. The reversal of 79779697209 is 90279697797.

The square root of 79779697209 is 282453.

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

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-79779697209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (79779697219) 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, 800284 + ... + 894434.

Almost surely, 2^79779697209 is an apocalyptic number.

79779697209 is the 282453-rd square number.

79779697209 is the 141227-th centered octagonal number.

It is an amenable number.

79779697209 is a deficient number, since it is larger than the sum of its proper divisors (35458867180).

79779697209 is an frugal number, since it uses more digits than its factorization.

79779697209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188308 (or 94154 counting only the distinct ones).

The product of its (nonzero) digits is 189035532, while the sum is 72.

The spelling of 79779697209 in words is "seventy-nine billion, seven hundred seventy-nine million, six hundred ninety-seven thousand, two hundred nine".