78638039 has 4 divisors (see below), whose sum is σ = 83263824. Its totient is φ = 74012256.

The previous prime is 78638033. The next prime is 78638047. The reversal of 78638039 is 93083687.

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 78638039 - 2¹² = 78633943 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78638033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2312867 + ... + 2312900.

It is an arithmetic number, because the mean of its divisors is an integer number (20815956).

Almost surely, 2^78638039 is an apocalyptic number.

78638039 is a deficient number, since it is larger than the sum of its proper divisors (4625785).

78638039 is a wasteful number, since it uses less digits than its factorization.

78638039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4625784.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 78638039 is about 8867.8091431875. The cubic root of 78638039 is about 428.4277157136.

The spelling of 78638039 in words is "seventy-eight million, six hundred thirty-eight thousand, thirty-nine".