78789909 has 32 divisors (see below), whose sum is σ = 118698624. Its totient is φ = 46068480.

The previous prime is 78789901. The next prime is 78789913. The reversal of 78789909 is 90998787.

It is a happy number.

It is not a de Polignac number, because 78789909 - 2³ = 78789901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78789901) 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 31 ways as a sum of consecutive naturals, for example, 211047 + ... + 211419.

It is an arithmetic number, because the mean of its divisors is an integer number (3709332).

Almost surely, 2^78789909 is an apocalyptic number.

It is an amenable number.

78789909 is a deficient number, since it is larger than the sum of its proper divisors (39908715).

78789909 is a wasteful number, since it uses less digits than its factorization.

78789909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597.

The product of its (nonzero) digits is 2286144, while the sum is 57.

The square root of 78789909 is about 8876.3680072426. The cubic root of 78789909 is about 428.7033392203.

It can be divided in two parts, 78 and 789909, that added together give a palindrome (789987).

The spelling of 78789909 in words is "seventy-eight million, seven hundred eighty-nine thousand, nine hundred nine".