78669839 has 2 divisors, whose sum is σ = 78669840. Its totient is φ = 78669838.

The previous prime is 78669827. The next prime is 78669853. The reversal of 78669839 is 93896687.

It is a weak prime.

It is an emirp because it is prime and its reverse (93896687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78669839 - 2¹⁶ = 78604303 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78669889) 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 as a sum of consecutive naturals, namely, 39334919 + 39334920.

It is an arithmetic number, because the mean of its divisors is an integer number (39334920).

Almost surely, 2^78669839 is an apocalyptic number.

78669839 is a deficient number, since it is larger than the sum of its proper divisors (1).

78669839 is an equidigital number, since it uses as much as digits as its factorization.

78669839 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3919104, while the sum is 56.

The square root of 78669839 is about 8869.6019640117. The cubic root of 78669839 is about 428.4854577661.

The spelling of 78669839 in words is "seventy-eight million, six hundred sixty-nine thousand, eight hundred thirty-nine".