79787813 has 4 divisors (see below), whose sum is σ = 91186080. Its totient is φ = 68389548.

The previous prime is 79787809. The next prime is 79787837. The reversal of 79787813 is 31878797.

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 an emirpimes, since its reverse is a distinct semiprime: 31878797 = 167 ⋅190891.

It is a cyclic number.

It is not a de Polignac number, because 79787813 - 2² = 79787809 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 (79787863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5699123 + ... + 5699136.

It is an arithmetic number, because the mean of its divisors is an integer number (22796520).

Almost surely, 2^79787813 is an apocalyptic number.

It is an amenable number.

79787813 is a deficient number, since it is larger than the sum of its proper divisors (11398267).

79787813 is a wasteful number, since it uses less digits than its factorization.

79787813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11398266.

The product of its digits is 592704, while the sum is 50.

The square root of 79787813 is about 8932.4024204018. The cubic root of 79787813 is about 430.5056481763.

The spelling of 79787813 in words is "seventy-nine million, seven hundred eighty-seven thousand, eight hundred thirteen".