78664809 has 16 divisors (see below), whose sum is σ = 106210304. Its totient is φ = 51786000.

The previous prime is 78664787. The next prime is 78664813. The reversal of 78664809 is 90846687.

It is not a de Polignac number, because 78664809 - 2¹⁵ = 78632041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78664829) 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 15 ways as a sum of consecutive naturals, for example, 95172 + ... + 95994.

It is an arithmetic number, because the mean of its divisors is an integer number (6638144).

Almost surely, 2^78664809 is an apocalyptic number.

It is an amenable number.

78664809 is a deficient number, since it is larger than the sum of its proper divisors (27545495).

78664809 is a wasteful number, since it uses less digits than its factorization.

78664809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188.

The product of its (nonzero) digits is 580608, while the sum is 48.

The square root of 78664809 is about 8869.3184067323. The cubic root of 78664809 is about 428.4763253895.

The spelling of 78664809 in words is "seventy-eight million, six hundred sixty-four thousand, eight hundred nine".