78973391 has 4 divisors (see below), whose sum is σ = 90255312. Its totient is φ = 67691472.

The previous prime is 78973379. The next prime is 78973439. The reversal of 78973391 is 19337987.

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 78973391 - 2¹⁰ = 78972367 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78973691) 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, 5640950 + ... + 5640963.

It is an arithmetic number, because the mean of its divisors is an integer number (22563828).

Almost surely, 2^78973391 is an apocalyptic number.

78973391 is a deficient number, since it is larger than the sum of its proper divisors (11281921).

78973391 is a wasteful number, since it uses less digits than its factorization.

78973391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11281920.

The product of its digits is 285768, while the sum is 47.

The square root of 78973391 is about 8886.6974180513. The cubic root of 78973391 is about 429.0358621987.

The spelling of 78973391 in words is "seventy-eight million, nine hundred seventy-three thousand, three hundred ninety-one".