78557890079 has 4 divisors (see below), whose sum is σ = 78558535440. Its totient is φ = 78557244720.

The previous prime is 78557890057. The next prime is 78557890091. The reversal of 78557890079 is 97009875587.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 78557890079 - 2²⁴ = 78541112863 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78557889997 and 78557890024.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78557892079) 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, 78494 + ... + 404075.

It is an arithmetic number, because the mean of its divisors is an integer number (19639633860).

Almost surely, 2^78557890079 is an apocalyptic number.

78557890079 is a deficient number, since it is larger than the sum of its proper divisors (645361).

78557890079 is a wasteful number, since it uses less digits than its factorization.

78557890079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645360.

The product of its (nonzero) digits is 44452800, while the sum is 65.

The spelling of 78557890079 in words is "seventy-eight billion, five hundred fifty-seven million, eight hundred ninety thousand, seventy-nine".