78718043617 has 4 divisors (see below), whose sum is σ = 78793085700. Its totient is φ = 78643001536.

The previous prime is 78718043587. The next prime is 78718043687. The reversal of 78718043617 is 71634081787.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 63304572816 + 15413470801 = 251604^2 + 124151^2 .

It is a cyclic number.

It is not a de Polignac number, because 78718043617 - 2⁷ = 78718043489 is a prime.

It is a super-3 number, since 3×78718043617³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78718043687) 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, 37519468 + ... + 37521565.

It is an arithmetic number, because the mean of its divisors is an integer number (19698271425).

Almost surely, 2^78718043617 is an apocalyptic number.

It is an amenable number.

78718043617 is a deficient number, since it is larger than the sum of its proper divisors (75042083).

78718043617 is a wasteful number, since it uses less digits than its factorization.

78718043617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75042082.

The product of its (nonzero) digits is 1580544, while the sum is 52.

The spelling of 78718043617 in words is "seventy-eight billion, seven hundred eighteen million, forty-three thousand, six hundred seventeen".