78658791 has 4 divisors (see below), whose sum is σ = 104878392. Its totient is φ = 52439192.

The previous prime is 78658771. The next prime is 78658807. The reversal of 78658791 is 19785687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19785687 = 3 ⋅6595229.

It is a cyclic number.

It is not a de Polignac number, because 78658791 - 2⁷ = 78658663 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78658721) 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, 13109796 + ... + 13109801.

It is an arithmetic number, because the mean of its divisors is an integer number (26219598).

Almost surely, 2^78658791 is an apocalyptic number.

78658791 is a deficient number, since it is larger than the sum of its proper divisors (26219601).

78658791 is a wasteful number, since it uses less digits than its factorization.

78658791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26219600.

The product of its digits is 846720, while the sum is 51.

The square root of 78658791 is about 8868.9791408031. The cubic root of 78658791 is about 428.4653987066.

The spelling of 78658791 in words is "seventy-eight million, six hundred fifty-eight thousand, seven hundred ninety-one".