78623209 has 4 divisors (see below), whose sum is σ = 89855104. Its totient is φ = 67391316.

The previous prime is 78623201. The next prime is 78623243. The reversal of 78623209 is 90232687.

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.

It is a cyclic number.

It is not a de Polignac number, because 78623209 - 2³ = 78623201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78623201) 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, 5615937 + ... + 5615950.

It is an arithmetic number, because the mean of its divisors is an integer number (22463776).

Almost surely, 2^78623209 is an apocalyptic number.

It is an amenable number.

78623209 is a deficient number, since it is larger than the sum of its proper divisors (11231895).

78623209 is a wasteful number, since it uses less digits than its factorization.

78623209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11231894.

The product of its (nonzero) digits is 36288, while the sum is 37.

The square root of 78623209 is about 8866.9729333071. The cubic root of 78623209 is about 428.4007822577.

The spelling of 78623209 in words is "seventy-eight million, six hundred twenty-three thousand, two hundred nine".