78855791 has 4 divisors (see below), whose sum is σ = 90120912. Its totient is φ = 67590672.

The previous prime is 78855787. The next prime is 78855793. The reversal of 78855791 is 19755887.

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

It is a cyclic number.

It is not a de Polignac number, because 78855791 - 2² = 78855787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78855793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5632550 + ... + 5632563.

It is an arithmetic number, because the mean of its divisors is an integer number (22530228).

Almost surely, 2^78855791 is an apocalyptic number.

78855791 is a deficient number, since it is larger than the sum of its proper divisors (11265121).

78855791 is a wasteful number, since it uses less digits than its factorization.

78855791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11265120.

The product of its digits is 705600, while the sum is 50.

The square root of 78855791 is about 8880.0783217267. The cubic root of 78855791 is about 428.8227959932.

The spelling of 78855791 in words is "seventy-eight million, eight hundred fifty-five thousand, seven hundred ninety-one".