78439 has 2 divisors, whose sum is σ = 78440. Its totient is φ = 78438.

The previous prime is 78437. The next prime is 78467. The reversal of 78439 is 93487.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (93487) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78439 - 2¹ = 78437 is a prime.

Together with 78437, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 78439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39219 + 39220.

It is an arithmetic number, because the mean of its divisors is an integer number (39220).

2⁷⁸⁴³⁹ is an apocalyptic number.

78439 is a deficient number, since it is larger than the sum of its proper divisors (1).

78439 is an equidigital number, since it uses as much as digits as its factorization.

It is an anagram of its base 12 representation: 78439 = (39487)₁₂.

78439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 31.

The square root of 78439 is about 280.0696341984. The cubic root of 78439 is about 42.8065949019.

The spelling of 78439 in words is "seventy-eight thousand, four hundred thirty-nine".