78485809 has 4 divisors (see below), whose sum is σ = 78525504. Its totient is φ = 78446116.

The previous prime is 78485801. The next prime is 78485839. The reversal of 78485809 is 90858487.

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 78485809 - 2³ = 78485801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78485801) 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 3 ways as a sum of consecutive naturals, for example, 16717 + ... + 20890.

It is an arithmetic number, because the mean of its divisors is an integer number (19631376).

Almost surely, 2^78485809 is an apocalyptic number.

It is an amenable number.

78485809 is a deficient number, since it is larger than the sum of its proper divisors (39695).

78485809 is a wasteful number, since it uses less digits than its factorization.

78485809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39694.

The product of its (nonzero) digits is 645120, while the sum is 49.

The square root of 78485809 is about 8859.2216926771. The cubic root of 78485809 is about 428.1510824964.

The spelling of 78485809 in words is "seventy-eight million, four hundred eighty-five thousand, eight hundred nine".