78909 has 8 divisors (see below), whose sum is σ = 108960. Its totient is φ = 50736.

The previous prime is 78901. The next prime is 78919. The reversal of 78909 is 90987.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78909 - 2³ = 78901 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 78909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 367 + ... + 540.

It is an arithmetic number, because the mean of its divisors is an integer number (13620).

2⁷⁸⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

78909 is a deficient number, since it is larger than the sum of its proper divisors (30051).

78909 is a wasteful number, since it uses less digits than its factorization.

78909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 939.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 78909 is about 280.9074580712. The cubic root of 78909 is about 42.8919225614.

The spelling of 78909 in words is "seventy-eight thousand, nine hundred nine".