78665759 has 4 divisors (see below), whose sum is σ = 78685320. Its totient is φ = 78646200.

The previous prime is 78665753. The next prime is 78665771. The reversal of 78665759 is 95756687.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95756687 = 13 ⋅7365899.

It is a cyclic number.

It is not a de Polignac number, because 78665759 - 2²⁴ = 61888543 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78665759.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78665753) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1292 + ... + 12609.

It is an arithmetic number, because the mean of its divisors is an integer number (19671330).

Almost surely, 2^78665759 is an apocalyptic number.

78665759 is a deficient number, since it is larger than the sum of its proper divisors (19561).

78665759 is a wasteful number, since it uses less digits than its factorization.

78665759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19560.

The product of its digits is 3175200, while the sum is 53.

The square root of 78665759 is about 8869.3719619824. The cubic root of 78665759 is about 428.4780502221.

The spelling of 78665759 in words is "seventy-eight million, six hundred sixty-five thousand, seven hundred fifty-nine".