78816545 has 4 divisors (see below), whose sum is σ = 94579860. Its totient is φ = 63053232.

The previous prime is 78816523. The next prime is 78816547. The reversal of 78816545 is 54561887.

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: 54561887 = 151 ⋅361337.

It can be written as a sum of positive squares in 2 ways, for example, as 43151761 + 35664784 = 6569^2 + 5972^2 .

It is a cyclic number.

It is not a de Polignac number, because 78816545 - 2⁶ = 78816481 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78816496 and 78816505.

It is not an unprimeable number, because it can be changed into a prime (78816547) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 7881650 + ... + 7881659.

It is an arithmetic number, because the mean of its divisors is an integer number (23644965).

Almost surely, 2^78816545 is an apocalyptic number.

It is an amenable number.

78816545 is a deficient number, since it is larger than the sum of its proper divisors (15763315).

78816545 is a wasteful number, since it uses less digits than its factorization.

78816545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15763314.

The product of its digits is 268800, while the sum is 44.

The square root of 78816545 is about 8877.8682689033. The cubic root of 78816545 is about 428.7516434416.

The spelling of 78816545 in words is "seventy-eight million, eight hundred sixteen thousand, five hundred forty-five".