78719408809 has 4 divisors (see below), whose sum is σ = 79530949204. Its totient is φ = 77907868416.

The previous prime is 78719408797. The next prime is 78719408813. The reversal of 78719408809 is 90880491787.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90880491787 = 43 ⋅2113499809.

It can be written as a sum of positive squares in 2 ways, for example, as 64029241600 + 14690167209 = 253040^2 + 121203^2 .

It is a cyclic number.

It is not a de Polignac number, because 78719408809 - 2⁷ = 78719408681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78719402809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 405770052 + ... + 405770245.

It is an arithmetic number, because the mean of its divisors is an integer number (19882737301).

Almost surely, 2^78719408809 is an apocalyptic number.

It is an amenable number.

78719408809 is a deficient number, since it is larger than the sum of its proper divisors (811540395).

78719408809 is an equidigital number, since it uses as much as digits as its factorization.

78719408809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 811540394.

The product of its (nonzero) digits is 8128512, while the sum is 61.

The spelling of 78719408809 in words is "seventy-eight billion, seven hundred nineteen million, four hundred eight thousand, eight hundred nine".