79779802798081 has 4 divisors (see below), whose sum is σ = 81285082096212. Its totient is φ = 78274523499952.

The previous prime is 79779802798063. The next prime is 79779802798093. The reversal of 79779802798081 is 18089720897797.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 58265604842481 + 21514197955600 = 7633191^2 + 4638340^2 .

It is a cyclic number.

It is not a de Polignac number, because 79779802798081 - 2⁷ = 79779802797953 is a prime.

It is a super-2 number, since 2×79779802798081² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 79779802797986 and 79779802798004.

It is not an unprimeable number, because it can be changed into a prime (79779802798051) 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, 752639648986 + ... + 752639649091.

It is an arithmetic number, because the mean of its divisors is an integer number (20321270524053).

Almost surely, 2^{79779802798081} is an apocalyptic number.

It is an amenable number.

79779802798081 is a deficient number, since it is larger than the sum of its proper divisors (1505279298131).

79779802798081 is a wasteful number, since it uses less digits than its factorization.

79779802798081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1505279298130.

The product of its (nonzero) digits is 1792336896, while the sum is 82.

The spelling of 79779802798081 in words is "seventy-nine trillion, seven hundred seventy-nine billion, eight hundred two million, seven hundred ninety-eight thousand, eighty-one".