78686789 has 12 divisors (see below), whose sum is σ = 81252000. Its totient is φ = 76197528.

The previous prime is 78686737. The next prime is 78686791. The reversal of 78686789 is 98768687.

It is not a de Polignac number, because 78686789 - 2²⁰ = 77638213 is a prime.

It is a super-2 number, since 2×78686789² = 12383221526261042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78686719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 395312 + ... + 395510.

It is an arithmetic number, because the mean of its divisors is an integer number (6771000).

Almost surely, 2^78686789 is an apocalyptic number.

It is an amenable number.

78686789 is a deficient number, since it is larger than the sum of its proper divisors (2565211).

78686789 is a wasteful number, since it uses less digits than its factorization.

78686789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472 (or 425 counting only the distinct ones).

The product of its digits is 8128512, while the sum is 59.

The square root of 78686789 is about 8870.5574232965. The cubic root of 78686789 is about 428.5162290124.

It can be divided in two parts, 7868678 and 9, that added together give a palindrome (7868687).

The spelling of 78686789 in words is "seventy-eight million, six hundred eighty-six thousand, seven hundred eighty-nine".