78564638 has 4 divisors (see below), whose sum is σ = 117846960. Its totient is φ = 39282318.

The previous prime is 78564611. The next prime is 78564641. The reversal of 78564638 is 83646587.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83646587 = 31 ⋅2698277.

It is a junction number, because it is equal to n+sod(n) for n = 78564592 and 78564601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19641158 + ... + 19641161.

It is an arithmetic number, because the mean of its divisors is an integer number (29461740).

Almost surely, 2^78564638 is an apocalyptic number.

78564638 is a deficient number, since it is larger than the sum of its proper divisors (39282322).

78564638 is a wasteful number, since it uses less digits than its factorization.

78564638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39282321.

The product of its digits is 967680, while the sum is 47.

The square root of 78564638 is about 8863.6695561150. The cubic root of 78564638 is about 428.2943756130.

The spelling of 78564638 in words is "seventy-eight million, five hundred sixty-four thousand, six hundred thirty-eight".