79991578493 has 4 divisors (see below), whose sum is σ = 79992205728. Its totient is φ = 79990951260.

The previous prime is 79991578489. The next prime is 79991578529. The reversal of 79991578493 is 39487519997.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 79991578493 - 2² = 79991578489 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79991578453) 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, 46463 + ... + 402668.

It is an arithmetic number, because the mean of its divisors is an integer number (19998051432).

Almost surely, 2^79991578493 is an apocalyptic number.

It is an amenable number.

79991578493 is a deficient number, since it is larger than the sum of its proper divisors (627235).

79991578493 is a wasteful number, since it uses less digits than its factorization.

79991578493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 627234.

The product of its digits is 154314720, while the sum is 71.

The spelling of 79991578493 in words is "seventy-nine billion, nine hundred ninety-one million, five hundred seventy-eight thousand, four hundred ninety-three".