78866819 has 4 divisors (see below), whose sum is σ = 78974280. Its totient is φ = 78759360.

The previous prime is 78866813. The next prime is 78866833. The reversal of 78866819 is 91866887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91866887 = 7 ⋅13123841.

It is a cyclic number.

It is not a de Polignac number, because 78866819 - 2⁴ = 78866803 is a prime.

It is a super-3 number, since 3×78866819³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78866813) 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, 52622 + ... + 54099.

It is an arithmetic number, because the mean of its divisors is an integer number (19743570).

Almost surely, 2^78866819 is an apocalyptic number.

78866819 is a deficient number, since it is larger than the sum of its proper divisors (107461).

78866819 is a wasteful number, since it uses less digits than its factorization.

78866819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107460.

The product of its digits is 1161216, while the sum is 53.

The square root of 78866819 is about 8880.6992404878. The cubic root of 78866819 is about 428.8427853827.

The spelling of 78866819 in words is "seventy-eight million, eight hundred sixty-six thousand, eight hundred nineteen".