78769391 has 4 divisors (see below), whose sum is σ = 79241232. Its totient is φ = 78297552.

The previous prime is 78769351. The next prime is 78769403. The reversal of 78769391 is 19396787.

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 78769391 - 2¹⁰ = 78768367 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 (78769351) 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, 235670 + ... + 236003.

It is an arithmetic number, because the mean of its divisors is an integer number (19810308).

Almost surely, 2^78769391 is an apocalyptic number.

78769391 is a deficient number, since it is larger than the sum of its proper divisors (471841).

78769391 is a wasteful number, since it uses less digits than its factorization.

78769391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 471840.

The product of its digits is 571536, while the sum is 50.

The square root of 78769391 is about 8875.2121664780. The cubic root of 78769391 is about 428.6661225306. Note that the first 3 decimals are identical.

The spelling of 78769391 in words is "seventy-eight million, seven hundred sixty-nine thousand, three hundred ninety-one".