78239816 has 8 divisors (see below), whose sum is σ = 146699670. Its totient is φ = 39119904.

The previous prime is 78239809. The next prime is 78239893. The reversal of 78239816 is 61893287.

It can be written as a sum of positive squares in only one way, i.e., 48580900 + 29658916 = 6970^2 + 5446^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×78239816² = 12242937615427712, which contains 22 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4889981 + ... + 4889996.

Almost surely, 2^78239816 is an apocalyptic number.

It is an amenable number.

78239816 is a deficient number, since it is larger than the sum of its proper divisors (68459854).

78239816 is a wasteful number, since it uses less digits than its factorization.

78239816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9779983 (or 9779979 counting only the distinct ones).

The product of its digits is 145152, while the sum is 44.

The square root of 78239816 is about 8845.3273540327. The cubic root of 78239816 is about 427.7033055993.

The spelling of 78239816 in words is "seventy-eight million, two hundred thirty-nine thousand, eight hundred sixteen".