78646823 has 4 divisors (see below), whose sum is σ = 79979880. Its totient is φ = 77313768.

The previous prime is 78646807. The next prime is 78646829. The reversal of 78646823 is 32864687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32864687 = 313 ⋅104999.

It is a cyclic number.

It is not a de Polignac number, because 78646823 - 2⁴ = 78646807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78646829) 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, 666440 + ... + 666557.

It is an arithmetic number, because the mean of its divisors is an integer number (19994970).

Almost surely, 2^78646823 is an apocalyptic number.

78646823 is a deficient number, since it is larger than the sum of its proper divisors (1333057).

78646823 is a wasteful number, since it uses less digits than its factorization.

78646823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333056.

The product of its digits is 387072, while the sum is 44.

The square root of 78646823 is about 8868.3044038869. The cubic root of 78646823 is about 428.4436671496.

The spelling of 78646823 in words is "seventy-eight million, six hundred forty-six thousand, eight hundred twenty-three".